class CreateForkUsers < ActiveRecord::Migration[5.2] def change create_table :fork_users do |t| t.integer :project_id #原始项目id t.integer :fork_project_id #fork后的项目id t.integer :user_id #fork用户的id t.timestamps end add_index :fork_users, :project_id add_index :fork_users, :user_id projects = Project.where("forked_from_project_id is not null") projects.each do |p| ForkUser.create(project_id: p.forked_from_project_id, fork_project_id: p.id, user_id: p.user_id) end end end