Fix invalid arguments passed to find_by.

jobs/regular/remind_user.rb

@@ -3,7 +3,7 @@ class RemindUser < Jobs::Base
     sidekiq_options queue: 'low'
 
     def execute(args)
-      user = User.find_by(args[:user_id])
+      user = User.find_by(id: args[:user_id])
       raise Discourse::InvalidParameters.new(:user_id) if user.nil?
 
       PendingAssignsReminder.new.remind(user)

spec/jobs/regular/remind_user_spec.rb

@@ -0,0 +1,11 @@
+require 'rails_helper'
+
+RSpec.describe Jobs::RemindUser do
+  describe '#execute' do
+    it "should raise the right error when user_id is invalid" do
+      expect do
+        described_class.new.execute({})
+      end.to raise_error(Discourse::InvalidParameters)
+    end
+  end
+end