ADD db schema in models

app/models/pull_request_assign.rb

@@ -1,3 +1,19 @@
+# == Schema Information
+#
+# Table name: pull_request_assigns
+#
+#  id              :integer          not null, primary key
+#  pull_request_id :integer
+#  created_at      :datetime         not null
+#  updated_at      :datetime         not null
+#  user_login      :string(255)
+#
+# Indexes
+#
+#  index_pull_request_assigns_on_user_id_and_pull_request_id  (pull_request_id)
+#  index_pull_request_assigns_on_user_login                   (user_login)
+#
+
 class PullRequestAssign < ApplicationRecord
   belongs_to :user
   belongs_to :pull_request