Vim: detect Guardfiles as Ruby

Signed-off-by: Wincent Colaiuta <win@wincent.com>
*sh: add ~/code to CDPATH

This means I can do type "command-t" or "wikitext" or "wincent.com" etc
and be teleported magically to the right directory.

Signed-off-by: Wincent Colaiuta <win@wincent.com>