check_schema_file

# File activerecord/lib/active_record/tasks/database_tasks.rb, line 271
      def check_schema_file(filename)
        unless File.exist?(filename)
          message = %{#{filename} doesn't exist yet. Run `rails db:migrate` to create it, then try again.}.dup
          message << %{ If you do not intend to use a database, you should instead alter #{Rails.root}/config/application.rb to limit the frameworks that will be loaded.} if defined?(::Rails.root)
          Kernel.abort message
        end
      end