check_gem_dependencies

# File railties/lib/initializer.rb, line 250
    def check_gem_dependencies
      unloaded_gems = @configuration.gems.reject { |g| g.loaded? }
      if unloaded_gems.size > 0
        @gems_dependencies_loaded = false
        # don't print if the gems rake tasks are being run
        unless $rails_gem_installer
          puts %{These gems that this application depends on are missing:}
          unloaded_gems.each do |gem|
            puts " - #{gem.name}"
          end
          puts %{Run "rake gems:install" to install them.}
        end
      else
        @gems_dependencies_loaded = true
      end
    end