add path and path_with_namespace to api project entity

lib/api/entities.rb

@@ -21,6 +21,7 @@ module Gitlab
       expose :id, :name, :description, :default_branch
       expose :owner, using: Entities::UserBasic
       expose :private_flag, as: :private
+      expose :path, :path_with_namespace
       expose :issues_enabled, :merge_requests_enabled, :wall_enabled, :wiki_enabled, :created_at
       expose :namespace
     end