Yes, I know that. But for Chinese users, Docker is not a good choice: it’s intended for convenience but due to the network block(GFW) from within China, bundler install fails frequently for network error. So Chinese Docker user has to manually edit the Docker templates and configs and so on to fix that. It’s not easy, not to say that the Docker image download is VERY SLOW in China, and I’m afraid someday it may be totally unavailable. So a workaround for me is to use bundler package to avoid network download for installing Ruby Gems, which I’ve prepared in some special way before. In short, I need a way with highly custom installation script and Capistrano fits me. Rather complex, right?