entities: make Environment inherit EnvironmentBasic

lib/api/entities.rb

@@ -514,15 +514,14 @@ module API
       expose :duration
     end
 
-    class Environment < Grape::Entity
-      expose :id, :name, :external_url
-      expose :project, using: Entities::Project
-    end
-
     class EnvironmentBasic < Grape::Entity
       expose :id, :name, :external_url
     end
 
+    class Environment < EnvironmentBasic
+      expose :project, using: Entities::Project
+    end
+
     class Deployment < Grape::Entity
       expose :id, :iid, :ref, :sha, :created_at
       expose :user,        using: Entities::UserBasic