Update CI API docs for builds endpoint for runners

[ci skip]

doc/ci/api/README.md

@@ -10,6 +10,6 @@ you will find all relevant information.
 
 ## Resources
 
+- [Builds](builds.md)
 - [Runners](runners.md)
 - [Commits](commits.md)
-- [Builds](builds.md)

doc/ci/api/builds.md

 # Builds API
 
-This API used by runners to receive and update builds.
+API used by runners to receive and update builds.
 
-__Authentication is done by runner token__
+_**Note:** This API is intended to be used only by Runners as their own
+communication channel. For the consumer API see the
+[Builds API](../../api/builds.md)._
+
+## Authentication
+
+Unique runner token is required to authenticate. You can provide build token
+using a `token` parameter, or by sending `BUILD-TOKEN` header that contains it.
+
+`token` parameter and `BUILD-TOKEN` header can be interchangeable.
 
 ## Builds
 
 ### Runs oldest pending build by runner
 
-    POST /ci/builds/register
+    POST /builds/register
 
 Parameters:
 
   * `token` (required) - The unique token of runner
 
-Returns:
-
-```json
-{
-  "id": 48584,
-  "ref": "0.1.1",
-  "tag": true,
-  "sha": "d63117656af6ff57d99e50cc270f854691f335ad",
-  "status": "success",
-  "name": "pages",
-  "token": "9dd60b4f1a439d1765357446c1084c",
-  "stage": "test",
-  "project_id": 479,
-  "project_name": "test",
-  "commands": "echo commands",
-  "repo_url": "http://gitlab-ci-token:token@gitlab.example/group/test.git",
-  "before_sha": "0000000000000000000000000000000000000000",
-  "allow_git_fetch": false,
-  "options": {
-    "image": "docker:image",
-    "artifacts": {
-      "paths": [
-        "public"
-      ]
-    },
-    "cache": {
-      "paths": [
-        "vendor"
-      ]
-    }
-  },
-  "timeout": 3600,
-  "variables": [
-    {
-      "key": "CI_BUILD_TAG",
-      "value": "0.1.1",
-      "public": true
-    }
-  ],
-  "depends_on_builds": [
-    {
-      "id": 48584,
-      "ref": "0.1.1",
-      "tag": true,
-      "sha": "d63117656af6ff57d99e50cc270f854691f335ad",
-      "status": "success",
-      "name": "build",
-      "token": "9dd60b4f1a439d1765357446c1084c",
-      "stage": "build",
-      "project_id": 479,
-      "project_name": "test",
-      "artifacts_file": {
-        "filename": "artifacts.zip",
-        "size": 0
-      }
-    }
-  ]
-}
-```
 
 ### Update details of an existing build
 
-    PUT /ci/builds/:id
+    PUT /builds/:id
 
 Parameters:
 
   * `id` (required) - The ID of a project
   * `state` (optional) - The state of a build
   * `trace` (optional) - The trace of a build
+
+### Upload artifacts to build
+
+    POST /builds/:id/artifacts
+
+Parameters:
+
+  * `id` (required) - The ID of a build
+  * `token` (required) - The build authorization token
+  * `file` (required) - Artifacts file
+
+### Download the artifacts file from build
+
+    GET /builds/:id/artifacts
+
+Parameters:
+
+  * `id` (required) - The ID of a build
+  * `token` (required) - The build authorization token
+
+### Remove the artifacts file from build
+
+    DELETE /builds/:id/artifacts
+
+Parameters:
+
+  * ` id` (required) - The ID of a build
+  * `token` (required) - The build authorization token