diff --git a/db/migrate/20230520133729_add_user_login_uniq_index.rb b/db/migrate/20230520133729_add_user_login_uniq_index.rb
new file mode 100644
index 000000000..4527d9d29
--- /dev/null
+++ b/db/migrate/20230520133729_add_user_login_uniq_index.rb
@@ -0,0 +1,12 @@
+class AddForgeAppliedMessageUtf8mb4 < ActiveRecord::Migration[5.2]
+  def change
+
+    users = User.group("login").having("count(1) >1")
+    ids = users.pluck(:id)
+    logins = users.pluck(:login)
+    User.where(login: logins).where.not(id: ids).destroy_all
+
+    remove_index :users, :login
+    add_index :users, :login, unique: true
+  end
+end