While Heroku is nice and all, it suffers from the same disease as every other hosted-for-you solution:
$ git push heroku (...) -----> Gemfile detected, running Bundler version 1.0.7 (...) $ bundle --version Bundler version 1.0.10
It’s a whole three patch versions behind! Now I don’t really know (and maybe don’t even really want to know) what has changed between .7 and .10, but I can easily imagine things braking precisely because those minor inconsistencies in Bundler versions.
And sure, I could downgrade to .7, but to do that just because of Heroku? Thank you, but no. I want to ride the latest.