ADD db schema in models

app/models/compose_project.rb

@@ -1,3 +1,20 @@
+# == Schema Information
+#
+# Table name: compose_projects
+#
+#  id         :integer          not null, primary key
+#  user_id    :integer
+#  project_id :integer
+#  compose_id :integer
+#  position   :integer          default("0")
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+# Indexes
+#
+#  index_compose_projects_on_user_id_and_project_id_and_compose_id  (user_id,project_id,compose_id)
+#
+
 class ComposeProject < ApplicationRecord
   #组织的项目记录表
   belongs_to :compose