新增：反馈意见模型及接口

app/models/feedback.rb

@@ -0,0 +1,20 @@
+# == Schema Information
+#
+# Table name: feedbacks
+#
+#  id         :integer          not null, primary key
+#  user_id    :integer
+#  content    :text(65535)
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+# Indexes
+#
+#  index_feedbacks_on_user_id  (user_id)
+#
+
+class Feedback < ApplicationRecord
+
+  belongs_to :user
+
+end