Add token to runner details output in API

doc/api/runners.md

@@ -126,6 +126,7 @@ Example response:
             "path": "gitlab-org/gitlab-ce"
         }
     ],
+    "token": "205086a8e3b9a2b818ffac9b89d102",
     "revision": null,
     "tag_list": [
         "ruby",

lib/api/entities.rb

@@ -387,6 +387,7 @@ module API
       expose :tag_list
       expose :version, :revision, :platform, :architecture
       expose :contacted_at, as: :last_contact
+      expose :token, if: lambda { |runner, options| options[:user_is_admin] || !runner.is_shared? }
       expose :projects, with: Entities::RunnerProjectDetails
     end
 

lib/api/runners.rb

@@ -33,7 +33,7 @@ module API
         runner = get_runner(params[:id])
         can_show_runner?(runner) unless current_user.is_admin?
 
-        present runner, with: Entities::RunnerDetails
+        present runner, with: Entities::RunnerDetails, user_is_admin: current_user.is_admin?
       end
 
       # Update runner's details