Fixed rubocop messages

Guardfile

@@ -23,7 +23,7 @@ guard "livereload", host: "railsgoat.dev", port: "35727" do
 end
 
 
-guard :rspec, cmd: 'bundle exec rspec' do
+guard :rspec, cmd: "bundle exec rspec" do
   watch(%r{^spec/.+_spec\.rb$})
   watch(%r{^lib/(.+)\.rb$})     { |m| "spec/lib/#{m[1]}_spec.rb" }
   watch("spec/spec_helper.rb")  { "spec" }

db/schema.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 # This file is auto-generated from the current state of the database. Instead
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.