Add documentation

doc/api/README.md

@@ -29,6 +29,7 @@ The following API resources are available:
   - [Group access requests](access_requests.md)
   - [Group badges](group_badges.md)
   - [Group issue boards](group_boards.md)
+  - [Group labels](group_labels.md)
   - [Group-level variables](group_level_variables.md)
   - [Group members](members.md)
   - [Group milestones](group_milestones.md)

doc/api/group_labels.md

+# Group Label API
+
+>**Note:** This feature was [introduced](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21368) in GitLab 11.8.
+
+This API supports managing of [group labels](../user/project/labels.md#project-labels-and-group-labels). It allows to list, create, update, and delete group labels. Furthermore, users can subscribe and unsubscribe to and from group labels.
+
+## List group labels
+
+Get all labels for a given group.
+
+```
+GET /groups/:id/labels
+```
+
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `id` | integer/string | yes | The ID or [URL-encoded path of the group](README.md#namespaced-path-encoding) owned by the authenticated user |
+
+```bash
+curl --header "PRIVATE-TOKEN: <your_access_token>" https://gitlab.example.com/api/v4/groups/5/labels
+```
+
+Example response:
+
+```json
+[
+  {
+    "id": 7,
+    "name": "bug",
+    "color": "#FF0000",
+    "description": null,
+    "open_issues_count": 0,
+    "closed_issues_count": 0,
+    "open_merge_requests_count": 0,
+    "subscribed": false
+  },
+  {
+    "id": 4,
+    "name": "feature",
+    "color": "#228B22",
+    "description": null,
+    "open_issues_count": 0,
+    "closed_issues_count": 0,
+    "open_merge_requests_count": 0,
+    "subscribed": false
+  }
+]
+```
+
+## Create a new group label
+
+Create a new group label for a given group.
+
+```
+POST /groups/:id/labels
+```
+
+| Attribute     | Type    | Required | Description                  |
+| ------------- | ------- | -------- | ---------------------------- |
+| `id` | integer/string | yes | The ID or [URL-encoded path of the group](README.md#namespaced-path-encoding) owned by the authenticated user |
+| `name`        | string  | yes      | The name of the label        |
+| `color`       | string  | yes      | The color of the label given in 6-digit hex notation with leading '#' sign (e.g. #FFAABB) or one of the [CSS color names](https://developer.mozilla.org/en-US/docs/Web/CSS/color_value#Color_keywords) |
+| `description` | string  | no       | The description of the label |
+
+```bash
+curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" --header "Content-Type: application/json" --data '{"name": "Feature Proposal", "color": "#FFA500", "description": "Describes new ideas" }' https://gitlab.example.com/api/v4/groups/5/labels
+```
+
+Example response:
+
+```json
+{
+  "id": 9,
+  "name": "Feature Proposal",
+  "color": "#FFA500",
+  "description": "Describes new ideas",
+  "open_issues_count": 0,
+  "closed_issues_count": 0,
+  "open_merge_requests_count": 0,
+  "subscribed": false
+}
+```
+
+## Update a group label
+
+Updates an existing group label. At least one parameter is required, to update the group label.
+
+```
+PUT /groups/:id/labels
+```
+
+| Attribute     | Type    | Required | Description                  |
+| ------------- | ------- | -------- | ---------------------------- |
+| `id` | integer/string | yes | The ID or [URL-encoded path of the group](README.md#namespaced-path-encoding) owned by the authenticated user |
+| `name`        | string  | yes      | The name of the label        |
+| `new_name`    | string  | no      | The new name of the label        |
+| `color`       | string  | no      | The color of the label given in 6-digit hex notation with leading '#' sign (e.g. #FFAABB) or one of the [CSS color names](https://developer.mozilla.org/en-US/docs/Web/CSS/color_value#Color_keywords) |
+| `description` | string  | no       | The description of the label |
+
+```bash
+curl --request PUT --header "PRIVATE-TOKEN: <your_access_token>" --header "Content-Type: application/json" --data '{"name": "Feature Proposal", "new_name": "Feature Idea" }' https://gitlab.example.com/api/v4/groups/5/labels
+```
+
+Example response:
+
+```json
+{
+  "id": 9,
+  "name": "Feature Idea",
+  "color": "#FFA500",
+  "description": "Describes new ideas",
+  "open_issues_count": 0,
+  "closed_issues_count": 0,
+  "open_merge_requests_count": 0,
+  "subscribed": false
+}
+```
+
+## Delete a group label
+
+Deletes a group label with a given name.
+
+```
+DELETE /groups/:id/labels
+```
+
+| Attribute | Type    | Required | Description           |
+| --------- | ------- | -------- | --------------------- |
+| `id`      | integer/string    | yes      | The ID or [URL-encoded path of the group](README.md#namespaced-path-encoding) owned by the authenticated user |
+| `name`    | string  | yes      | The name of the label |
+
+```bash
+curl --request DELETE --header "PRIVATE-TOKEN: <your_access_token>" https://gitlab.example.com/api/v4/groups/5/labels?name=bug
+```
+
+## Subscribe to a group label
+
+Subscribes the authenticated user to a group label to receive notifications. If
+the user is already subscribed to the label, the status code `304` is returned.
+
+```
+POST /groups/:id/labels/:label_id/subscribe
+```
+
+| Attribute  | Type              | Required | Description                          |
+| ---------- | ----------------- | -------- | ------------------------------------ |
+| `id`      | integer/string    | yes      | The ID or [URL-encoded path of the group](README.md#namespaced-path-encoding) owned by the authenticated user |
+| `label_id` | integer or string | yes      | The ID or title of a group's label |
+
+```bash
+curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" https://gitlab.example.com/api/v4/groups/5/labels/9/subscribe
+```
+
+Example response:
+
+```json
+{
+  "id": 9,
+  "name": "Feature Idea",
+  "color": "#FFA500",
+  "description": "Describes new ideas",
+  "open_issues_count": 0,
+  "closed_issues_count": 0,
+  "open_merge_requests_count": 0,
+  "subscribed": true
+}
+```
+
+## Unsubscribe from a group label
+
+Unsubscribes the authenticated user from a group label to not receive
+notifications from it. If the user is not subscribed to the label, the status
+code `304` is returned.
+
+```
+POST /groups/:id/labels/:label_id/unsubscribe
+```
+
+| Attribute  | Type              | Required | Description                          |
+| ---------- | ----------------- | -------- | ------------------------------------ |
+| `id`      | integer/string    | yes      | The ID or [URL-encoded path of the group](README.md#namespaced-path-encoding) owned by the authenticated user |
+| `label_id` | integer or string | yes      | The ID or title of a group's label |
+
+```bash
+curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" https://gitlab.example.com/api/v4/groups/5/labels/9/unsubscribe
+```
+
+Example response:
+
+```json
+{
+  "id": 9,
+  "name": "Feature Idea",
+  "color": "#FFA500",
+  "description": "Describes new ideas",
+  "open_issues_count": 0,
+  "closed_issues_count": 0,
+  "open_merge_requests_count": 0,
+  "subscribed": false
+}
+```