Set PATH variables to allow gems such as Bundler to be found and for the
`ruby-info` function to properly work.
A default Ruby must be set in ~/.ruby-version; for more information, see
https://github.com/postmodern/chruby#default-ruby.
Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>
Defining it breaks gems for all users who neither use RVM nor rbenv,
but have a different default Ruby version nonetheless.
Signed-off-by: Sorin Ionescu <sorin.ionescu@gmail.com>