ruby 1.9.1 compat: generate with --git option fails on call to String#inject

Using Ruby 1.9.1, the generator script does not work when using the --git/-g option because String in Ruby 1.9 is no longer an enumerable, and inject does not work with it.

$ ./script/generate resource foo -g
undefined method `inject' for #<String:0x153a36c>

A patch is attached to fix the issue.