Backport docs update for multiple assignees for MRs

This backports API and quick action docs.

doc/api/merge_requests.md

@@ -93,6 +93,14 @@ Parameters:
       "avatar_url": null,
       "web_url" : "https://gitlab.example.com/admin"
     },
+    "assignees": [{
+      "name": "Miss Monserrate Beier",
+      "username": "axel.block",
+      "id": 12,
+      "state": "active",
+      "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+      "web_url": "https://gitlab.example.com/axel.block"
+    }],
     "source_project_id": 2,
     "target_project_id": 3,
     "labels": [
@@ -227,6 +235,14 @@ Parameters:
       "avatar_url": null,
       "web_url" : "https://gitlab.example.com/admin"
     },
+    "assignees": [{
+      "name": "Miss Monserrate Beier",
+      "username": "axel.block",
+      "id": 12,
+      "state": "active",
+      "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+      "web_url": "https://gitlab.example.com/axel.block"
+    }],
     "source_project_id": 2,
     "target_project_id": 3,
     "labels": [
@@ -351,6 +367,14 @@ Parameters:
       "avatar_url": null,
       "web_url" : "https://gitlab.example.com/admin"
     },
+    "assignees": [{
+      "name": "Miss Monserrate Beier",
+      "username": "axel.block",
+      "id": 12,
+      "state": "active",
+      "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+      "web_url": "https://gitlab.example.com/axel.block"
+    }],
     "source_project_id": 2,
     "target_project_id": 3,
     "labels": [
@@ -445,6 +469,14 @@ Parameters:
     "avatar_url": null,
     "web_url" : "https://gitlab.example.com/admin"
   },
+  "assignees": [{
+    "name": "Miss Monserrate Beier",
+    "username": "axel.block",
+    "id": 12,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/axel.block"
+  }],
   "source_project_id": 2,
   "target_project_id": 3,
   "labels": [
@@ -629,6 +661,14 @@ Parameters:
     "avatar_url": "http://www.gravatar.com/avatar/e64c7d89f26bd1972efa854d13d7dd61?s=40&d=identicon",
     "web_url" : "https://gitlab.example.com/root"
   },
+  "assignees": [{
+    "name": "Miss Monserrate Beier",
+    "username": "axel.block",
+    "id": 12,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/axel.block"
+  }],
   "source_project_id": 4,
   "target_project_id": 4,
   "labels": [ ],
@@ -718,6 +758,7 @@ POST /projects/:id/merge_requests
 | `target_branch`            | string  | yes      | The target branch                                                               |
 | `title`                    | string  | yes      | Title of MR                                                                     |
 | `assignee_id`              | integer | no       | Assignee user ID                                                                |
+| `assignee_ids`             | Array[integer] | no  | The ID of the user(s) to assign the MR to. Set to `0` or provide an empty value to unassign all assignees.  |
 | `description`              | string  | no       | Description of MR                                                               |
 | `target_project_id`        | integer | no       | The target project (numeric id)                                                 |
 | `labels`                   | string  | no       | Labels for MR as a comma-separated list                                         |
@@ -843,6 +884,7 @@ PUT /projects/:id/merge_requests/:merge_request_iid
 | `target_branch`            | string  | no       | The target branch                                                               |
 | `title`                    | string  | no       | Title of MR                                                                     |
 | `assignee_id`              | integer | no       | The ID of the user to assign the merge request to. Set to `0` or provide an empty value to unassign all assignees.  |
+| `assignee_ids`             | Array[integer] | no  | The ID of the user(s) to assign the MR to. Set to `0` or provide an empty value to unassign all assignees.  |
 | `milestone_id`             | integer | no       | The global ID of a milestone to assign the merge request to. Set to `0` or provide an empty value to unassign a milestone.|
 | `labels`                   | string  | no       | Comma-separated label names for a merge request. Set to an empty string to unassign all labels.                    |
 | `description`              | string  | no       | Description of MR                                                               |
@@ -885,6 +927,14 @@ Must include at least one non-required attribute from above.
     "avatar_url": null,
     "web_url" : "https://gitlab.example.com/admin"
   },
+  "assignees": [{
+    "name": "Miss Monserrate Beier",
+    "username": "axel.block",
+    "id": 12,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/axel.block"
+  }],
   "source_project_id": 2,
   "target_project_id": 3,
   "labels": [
@@ -1030,6 +1080,14 @@ Parameters:
     "avatar_url": null,
     "web_url" : "https://gitlab.example.com/admin"
   },
+  "assignees": [{
+    "name": "Miss Monserrate Beier",
+    "username": "axel.block",
+    "id": 12,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/axel.block"
+  }],
   "source_project_id": 2,
   "target_project_id": 3,
   "labels": [
@@ -1180,6 +1238,14 @@ Parameters:
     "avatar_url": null,
     "web_url" : "https://gitlab.example.com/admin"
   },
+  "assignees": [{
+    "name": "Miss Monserrate Beier",
+    "username": "axel.block",
+    "id": 12,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/axel.block"
+  }],
   "source_project_id": 2,
   "target_project_id": 3,
   "labels": [
@@ -1436,6 +1502,14 @@ Example response:
     "avatar_url": null,
     "web_url" : "https://gitlab.example.com/admin"
   },
+  "assignees": [{
+    "name": "Miss Monserrate Beier",
+    "username": "axel.block",
+    "id": 12,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/axel.block"
+  }],
   "source_project_id": 2,
   "target_project_id": 3,
   "labels": [
@@ -1557,6 +1631,14 @@ Example response:
     "avatar_url": null,
     "web_url" : "https://gitlab.example.com/admin"
   },
+  "assignees": [{
+    "name": "Miss Monserrate Beier",
+    "username": "axel.block",
+    "id": 12,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/axel.block"
+  }],
   "source_project_id": 2,
   "target_project_id": 3,
   "labels": [
@@ -1698,6 +1780,14 @@ Example response:
       "avatar_url": "http://www.gravatar.com/avatar/733005fcd7e6df12d2d8580171ccb966?s=80&d=identicon",
       "web_url": "https://gitlab.example.com/barrett.krajcik"
     },
+    "assignees": [{
+      "name": "Miss Monserrate Beier",
+      "username": "axel.block",
+      "id": 12,
+      "state": "active",
+      "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+      "web_url": "https://gitlab.example.com/axel.block"
+    }],
     "source_project_id": 3,
     "target_project_id": 3,
     "labels": [],

doc/user/project/merge_requests/index.md

@@ -169,6 +169,28 @@ can easily apply them to the codebase directly from the UI. Read
 through the documentation on [Suggest changes](../../discussions/index.md#suggest-changes)
 to learn more.
 
+## Multiple assignees **[STARTER]**
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab-ee/issues/2004)
+in [GitLab Starter 11.11](https://about.gitlab.com/pricing).
+
+Multiple people often review merge requests at the same time. GitLab allows you to have multiple assignees for merge requests to indicate everyone that is reviewing or accountable for it.
+
+![multiple assignees for merge requests sidebar](img/multiple_assignees_for_merge_requests_sidebar.png)
+
+To assign multiple assignees to a merge request:
+
+1. From a merge request, expand the right sidebar and locate the **Assignees** section.
+1. Click on **Edit** and from the dropdown menu, select as many users as you want
+to assign the merge request to.
+
+Similarly, assignees are removed by deselecting them from the same dropdown menu.
+
+It's also possible to manage multiple assignees:
+
+- When creating a merge request.
+- Using [quick actions](../quick_actions.md#quick-actions-for-issues-and-merge-requests).
+
 ## Resolve conflicts
 
 When a merge request has conflicts, GitLab may provide the option to resolve

doc/user/project/quick_actions.md

@@ -26,9 +26,10 @@ discussions, and descriptions:
 | `/award :emoji:`           | Toggle emoji award             | ✓     | ✓             |
 | `/assign me`               | Assign yourself                | ✓     | ✓             |
 | `/assign @user`            | Assign one user                | ✓     | ✓             |
-| `/assign @user1 @user2`    | Assign multiple users **[STARTER]** | ✓ |              |
-| `/unassign`                | Remove assignee(s)             | ✓     | ✓             |
-| `/reassign @user1 @user2`  | Change assignee                | ✓     | ✓             |
+| `/assign @user1 @user2`    | Assign multiple users **[STARTER]** | ✓ | ✓            |
+| `/unassign @user1 @user2`  | Remove assignee(s) **[STARTER]** | ✓     | ✓             |
+| `/reassign @user1 @user2`  | Change assignee **[STARTER]**  | ✓     | ✓             |
+| `/unassign`                | Remove current assignee        | ✓     | ✓             |
 | `/milestone %milestone`    | Set milestone                  | ✓     | ✓             |
 | `/remove_milestone`        | Remove milestone               | ✓     | ✓             |
 | `/label ~label1 ~label2`   | Add label(s). Label names can also start without ~ but mixed syntax is not supported.                   | ✓     | ✓             |