pezra/rspec-mode — pull request #68 by dgtized (2013-09-11 00:58:51+00:00)
Title: yas-extra-modes is not a function

In addition, whether or not yas-extra-modes is nil, a single element, or
an existing list, this will correctly add rspec-mode to it, and convert
it to a list allowing the subsequent removal on disabling the mode to
always succeed.