add account access

db/migrate/20250518070555_account_accesses.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class AccountAccesses < ActiveRecord::Migration[8.0]
+  def change
+    create_table :account_accesses do |t|
+      t.references :account, null: false, foreign_key: true, index: false
+      t.references :user, null: false, foreign_key: false, index: false
+
+      t.index %i[account_id user_id], unique: true
+
+      t.timestamps
+    end
+  end
+end