Instead of `== "master\n"`, I would use:

``` ruby
`git rev-parse --abbrev-ref HEAD`.chomp == "master"
```

I get why you put this (we don't want odd spikes from PRs we don't merge to show up on the graphs) but it would be nice if there was some way to see the benchmarks for a PR before its merged.  Any thoughts on what we should do about that?