APi for commits. Better api docs

lib/api/entities.rb

@@ -17,6 +17,11 @@ module Gitlab
       expose :id, :url
     end
 
+    class Commit < Grape::Entity
+      expose :id, :short_id, :title,
+        :author_name, :author_email, :created_at
+    end
+
     class Project < Grape::Entity
       expose :id, :code, :name, :description, :path, :default_branch
       expose :owner, using: Entities::UserBasic