group_removed_users table to forbid users joining once removed

app/models/group_removed_account.rb

@@ -0,0 +1,13 @@
+# == Schema Information
+#
+# Table name: group_removed_accounts
+#
+#  id         :bigint(8)        not null, primary key
+#  group_id   :bigint(8)        not null
+#  account_id :bigint(8)        not null
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+
+class GroupRemovedAccount < ApplicationRecord
+end