class CreateAnnouncementMutes < ActiveRecord::Migration[5.2] def change create_table :announcement_mutes do |t| t.belongs_to :account, foreign_key: { on_delete: :cascade, index: false } t.belongs_to :announcement, foreign_key: { on_delete: :cascade } t.timestamps end add_index :announcement_mutes, [:account_id, :announcement_id], unique: true end end