Clarify the usage of chruby-exec (closes #215).
Clarify the usage of chruby-exec (closes #215).

regularfry/chruby,eunomie/chgo,regularfry/chruby,kbrock/chruby,kbrock/chruby,ngpestelos/chruby,postmodern/chruby,eunomie/chgo,ilikepi/chruby,postmodern/chruby,ngpestelos/chruby,ilikepi/chruby