Reverts "Merge pull request #6 from tprado/move-rake-to-default-gemset"

because it was not causing the issue after all.

This reverts commit 8cd5aab7706c74a38943a90f5270dc87b71cb94d, reversing
changes made to 62cb542fbaa5bb2632010361bb9dc7a8d5e90486.