我正在尝试使用rails-composer来启动一个项目。在 composer 安装 gems 之后，我得到一个错误并且脚本停止。这是错误：
Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed.
composer Running 'after bundler' callbacks.
The template [https://raw.github.com/RailsApps/rails-composer/master/composer.rb] could not be loaded. Error: You have already activated builder 3.0.0, but your Gemfile requires builder 3.0.2. Using bundle exec may solve this.
我不确定如何使用 bundle exec 来解决这个问题。