Add runners API documentation [ci-skip]

doc/api/README.md

@@ -32,6 +32,7 @@ following locations:
 - [Builds](builds.md)
 - [Build triggers](build_triggers.md)
 - [Build Variables](build_variables.md)
+- [Runners](runners.md)
 
 ## Authentication
 

doc/api/runners.md

+# Runners API
+
+## List runners
+
+Get a list of runners.
+
+```
+GET /runners
+```
+
+| Attribute | Type    | required | Description         |
+|-----------|---------|----------|---------------------|
+| `scope`   | string  | no       | The scope of runners to show, one of: `specific`, `shared`, `active`, `paused`, `online`; showing all runners if none provided |
+
+```
+curl -H "PRIVATE_TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/runners"
+```
+
+```json
+[
+    {
+        "active": true,
+        "description": "test-1-20150125",
+        "id": 6,
+        "is_shared": false,
+        "name": null
+    },
+    {
+        "active": true,
+        "description": "test-2-20150125",
+        "id": 8,
+        "is_shared": false,
+        "name": null
+    }
+]
+```
+
+## Get runner's details
+
+Get details of a runner.
+
+```
+GET /runners/:id
+```
+
+| Attribute | Type    | required | Description         |
+|-----------|---------|----------|---------------------|
+| `id`      | integer | yes      | The ID of a runner  |
+
+```
+curl -H "PRIVATE_TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/runners/6"
+```
+
+```json
+{
+    "active": true,
+    "architecture": null,
+    "description": "test-1-20150125",
+    "id": 6,
+    "is_shared": false,
+    "last_contact": "2016-01-25T16:39:48.066Z",
+    "name": null,
+    "platform": null,
+    "revision": null,
+    "tag_list": [
+        "ruby",
+        "mysql"
+    ],
+    "version": null
+}
+```
+
+## Update runner's details
+
+Update details of a runner.
+
+```
+PUT /runners/:id
+```
+
+| Attribute     | Type    | required | Description         |
+|---------------|---------|----------|---------------------|
+| `id`          | integer | yes      | The ID of a runner  |
+| `description` | string  | no       | The description of a runner |
+| `active`      | boolean | no       | The state of a runner; can be set to `true` or `false` |
+| `tag_list`    | array   | no       | The list of tags for a runner; put array of tags, that should be finally assigned to a runner |
+
+```
+curl -X PUT -H "PRIVATE_TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/runners/6" -F "description=test-1-20150125-test" -F "tag_list=ruby,mysql,tag1,tag2"
+```
+
+```json
+{
+    "active": true,
+    "architecture": null,
+    "description": "test-1-20150125-test",
+    "id": 6,
+    "is_shared": false,
+    "last_contact": "2016-01-25T16:39:48.066Z",
+    "name": null,
+    "platform": null,
+    "revision": null,
+    "tag_list": [
+        "ruby",
+        "mysql",
+        "tag1",
+        "tag2"
+    ],
+    "version": null
+}
+```
+
+## Remove a runner
+
+Remove a runner.
+
+```
+DELETE /runners/:id
+```
+
+| Attribute | Type    | required | Description         |
+|-----------|---------|----------|---------------------|
+| `id`      | integer | yes      | The ID of a runner  |
+
+```
+curl -X DELETE -H "PRIVATE_TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/runners/6"
+```
+
+```json
+{
+    "active": true,
+    "architecture": null,
+    "description": "test-1-20150125-test",
+    "id": 6,
+    "is_shared": false,
+    "last_contact": "2016-01-25T16:39:48.066Z",
+    "name": null,
+    "platform": null,
+    "revision": null,
+    "tag_list": [],
+    "version": null
+}
+```
+
+## List project's runners
+
+List all runners (*shared* and *specific*) available in project. Shared runners are listed if at least one shared runner
+is defined **and** shared runners usage is enabled in project's settings.
+
+```
+GET /projects/:id/runners
+```
+
+| Attribute | Type    | required | Description         |
+|-----------|---------|----------|---------------------|
+| `id`      | integer | yes      | The ID of a project |
+
+```
+curl -X DELETE -H "PRIVATE_TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/project/9/runners"
+```
+
+```json
+[
+    {
+        "active": true,
+        "description": "test-2-20150125",
+        "id": 8,
+        "is_shared": false,
+        "name": null
+    },
+    {
+        "active": true,
+        "description": "development_runner",
+        "id": 5,
+        "is_shared": true,
+        "name": null
+    }
+]
+```
+
+## Enable a runner in project
+
+Enable available specific runner in project.
+
+```
+PUT /projects/:id/runners/:runner_id
+```
+
+| Attribute   | Type    | required | Description         |
+|-------------|---------|----------|---------------------|
+| `id`        | integer | yes      | The ID of a project |
+| `runner_id` | integer | yes      | The ID of a runner  |
+
+```
+curl -X PUT -H "PRIVATE_TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/project/9/runners/9"
+```
+
+```json
+{
+    "active": true,
+    "description": "test-2016-02-01",
+    "id": 9,
+    "is_shared": false,
+    "name": null
+}
+```
+
+## Disable a runner from project
+
+Disable a specific runner from project. It works only, if the project isn't an only project associated with the
+specified runner. If so, then an error is returned and user should use the [remove a runner](#remove-a-runner) feature.
+
+```
+PUT /projects/:id/runners/:runner_id
+```
+
+| Attribute   | Type    | required | Description         |
+|-------------|---------|----------|---------------------|
+| `id`        | integer | yes      | The ID of a project |
+| `runner_id` | integer | yes      | The ID of a runner  |
+
+```
+curl -X DELETE -H "PRIVATE_TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/project/9/runners/9"
+```
+
+```json
+{
+    "active": true,
+    "description": "test-2016-02-01",
+    "id": 9,
+    "is_shared": false,
+    "name": null
+}
+```