move ./bin to front of PATH
move ./bin to front of PATH

If ./bin exists in the PATH, move it to the front of PATH so that gem
executables in the ./bin binstubs dir get chosen over the ones from the
gem installation.

JeanMertz/chruby-fish,rstacruz/chruby-fish,rstacruz/chruby-fish,JeanMertz/chruby-fish