fix create admin user rake

lib/tasks/create_user.rake

@@ -1,8 +1,9 @@
 namespace :user do
   task :create_admin, [:email, :name] do  |_, args|
-    User.create!(
+    user = User.create!(
       email: args[:email],
-      name: args[:name]
+      name: args[:name],
+      roles: [:admin]
     )
   end
 end