Add a system hook for when a project is updated.

This sends a project_update hook when a repo is updated.  This does not include
renaming or transferring a project.  Those are covered by project_rename and
project_transfer.  This will get called, however, when the visibility is
changed.

app/services/projects/update_service.rb

@@ -22,6 +22,8 @@ module Projects
       if project.update_attributes(params.except(:default_branch))
         if project.previous_changes.include?('path')
           project.rename_repo
+        else
+          system_hook_service.execute_hooks_for(project, :update)
         end
 
         success

changelogs/unreleased/add_project_update_hook.yml

+---
+title: Add system hook for when a project is updated (other than rename/transfer)
+merge_request: 5711
+author: Tommy Beadle

doc/system_hooks/system_hooks.md

 # System hooks
 
-Your GitLab instance can perform HTTP POST requests on the following events: `project_create`, `project_destroy`, `project_rename`, `project_transfer`, `user_add_to_team`, `user_remove_from_team`, `user_create`, `user_destroy`, `key_create`, `key_destroy`, `group_create`, `group_destroy`, `user_add_to_group` and `user_remove_from_group`.
+Your GitLab instance can perform HTTP POST requests on the following events: `project_create`, `project_destroy`, `project_rename`, `project_transfer`, `project_update`, `user_add_to_team`, `user_remove_from_team`, `user_create`, `user_destroy`, `key_create`, `key_destroy`, `group_create`, `group_destroy`, `user_add_to_group` and `user_remove_from_group`.
 
 System hooks can be used, e.g. for logging or changing information in a LDAP server.
 
@@ -88,6 +88,23 @@ X-Gitlab-Event: System Hook
 }
 ```
 
+**Project updated:**
+
+```json
+{
+          "created_at": "2012-07-21T07:30:54Z",
+          "updated_at": "2012-07-21T07:38:22Z",
+          "event_name": "project_update",
+                "name": "StoreCloud",
+         "owner_email": "johnsmith@gmail.com",
+          "owner_name": "John Smith",
+                "path": "storecloud",
+ "path_with_namespace": "jsmith/storecloud",
+          "project_id": 74,
+  "project_visibility": "private",
+}
+```
+
 **New Team Member:**
 
 ```json

spec/services/system_hooks_service_spec.rb

@@ -12,6 +12,7 @@ describe SystemHooksService, services: true do
     it { expect(event_data(user, :create)).to include(:event_name, :name, :created_at, :updated_at, :email, :user_id, :username) }
     it { expect(event_data(user, :destroy)).to include(:event_name, :name, :created_at, :updated_at, :email, :user_id, :username) }
     it { expect(event_data(project, :create)).to include(:event_name, :name, :created_at, :updated_at, :path, :project_id, :owner_name, :owner_email, :project_visibility) }
+    it { expect(event_data(project, :update)).to include(:event_name, :name, :created_at, :updated_at, :path, :project_id, :owner_name, :owner_email, :project_visibility) }
     it { expect(event_data(project, :destroy)).to include(:event_name, :name, :created_at, :updated_at, :path, :project_id, :owner_name, :owner_email, :project_visibility) }
     it { expect(event_data(project_member, :create)).to include(:event_name, :created_at, :updated_at, :project_name, :project_path, :project_path_with_namespace, :project_id, :user_name, :user_username, :user_email, :user_id, :access_level, :project_visibility) }
     it { expect(event_data(project_member, :destroy)).to include(:event_name, :created_at, :updated_at, :project_name, :project_path, :project_path_with_namespace, :project_id, :user_name, :user_username, :user_email, :user_id, :access_level, :project_visibility) }
@@ -68,6 +69,7 @@ describe SystemHooksService, services: true do
     it { expect(event_name(project, :destroy)).to eq "project_destroy" }
     it { expect(event_name(project, :rename)).to eq "project_rename" }
     it { expect(event_name(project, :transfer)).to eq "project_transfer" }
+    it { expect(event_name(project, :update)).to eq "project_update" }
     it { expect(event_name(project_member, :create)).to eq "user_add_to_team" }
     it { expect(event_name(project_member, :destroy)).to eq "user_remove_from_team" }
     it { expect(event_name(key, :create)).to eq 'key_create' }