Make a file for one line configure.

Hi divoxx, I love this goproj so much. It help me create diffrent go project easily! But I think the path config doesn't look like a best way to solve the path-problem. Cause when I use the rvm and the other version manager, the `$PATH` aways changed. so i make a file to add the bin path, make the alias BTW.
So, I can just do `[[ -d $HOME/.goproj ]] && source "$HOME/.goproj/goproj.sh"` in one line, it will help me do the stuff things. It can make my `rc` files clean!