This fixes the following error I've been seeing lately in RubyMine:
> Error:Your `bin/bundle` was not generated by Bundler, so this binstub cannot run.
> Replace `bin/bundle` by running `bundle binstubs bundler --force`, then run this command again.
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
Commit b516ecc added `bin/` to the .gitignore file. Now that Discourse
runs using Rails 4 by default, however, we should include the binstubs
generated by `rake rails:update:bin` in version control as this is the
recommendation of the Rails core team. Additionally, for those wishing
to deploy Discourse to Heroku, these binstubs are actually mandatory
according to [this article](https://devcenter.heroku.com/articles/rails4).
Other binstubs can continue to be ignored.
Signed-off-by: David Celis <me@davidcel.is>
