add .ruby-version to gitignore
remove some things I never used
no homebrew stuff when no brew
__git_ps1 on fedora
not sure if this is a fix. but it works.
word-jumping readline keybindings updated
bash prompt needs homebrew path set up on macos
chruby
provide which_ruby for chruby
make rbenv stuff conditional
try chruby auto-switching
tmux: configure base-index to 1