Fix ubuntu deployment

NOTE: This includes the commit I added in https://github.com/hotsh/rstat.us/pull/811 since this wouldn't pass tests on travis without that one (and that won't pass tests on travis without this one)

When deploying to heroku or running on travis, I was seeing:

```
    You are trying to install in deployment mode after changing
           your Gemfile. Run `bundle install` elsewhere and add the
           updated Gemfile.lock to version control.
           You have added to the Gemfile:
           * therubyracer (~> 0.11.3)
```

I assume because of the conditional we had for platform. Sooo let's take that out.