Fixes 'Unhandled exception: no implicit conversion of Pathname into S…

[tonybyrne]

…tring (TypeError)' exception when running on Ruby 2.2.2.

I spotted the above issue after upgrading our Rails app to Ruby 2.2.2. Concatenating a Pathname to a String, no longer 'casts' the Pathname to a String. You either need to call Pathname#to_s, or use File#join. I opted for the latter - hope it helps.