class CreateListAccounts < ActiveRecord::Migration[5.1] def change create_table :list_accounts do |t| t.belongs_to :list, foreign_key: { on_delete: :cascade }, null: false t.belongs_to :account, foreign_key: { on_delete: :cascade }, null: false t.belongs_to :follow, foreign_key: { on_delete: :cascade }, null: false end add_index :list_accounts, [:account_id, :list_id], unique: true add_index :list_accounts, [:list_id, :account_id] end end