init project

app/models/relationship.rb

@@ -0,0 +1,8 @@
+# TODO: 已废弃
+class Relationship < ApplicationRecord
+  belongs_to :follower, class_name: "User"
+  belongs_to :followed, class_name: "User"
+
+  validates :follower_id, presence: true
+  validates :followed_id, presence: true
+end