Short answer: Yes!
Longer Answer: Yes, but you have to generate your app before going offline, after all gems are installed there is no need to go online any more.
If you want install any single new gem on your app.then you need to go online.
Your developing a web-application.
Elmer,Try to get a internet connection asap.
That will be more helpful for you.
Thanks,
Saikiran Mothe
