install: add asdf

install

@@ -96,10 +96,22 @@ fi
 git config --global user.email "paul@blacksun.org.uk"
 git config --global user.name "Paul Walker"
 
+git clone https://github.com/rbenv/rbenv.git ~/.rbenv
+git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build
+
 if [ ! -d "$HOME/.asdf" ] ; then
   git clone https://github.com/asdf-vm/asdf.git ~/.asdf
 fi
 
+# Add and install these ones.
+for plugin in golang erlang elixir ; do
+  asdf plugin add $plugin
+  asdf install $plugin latest
+  asdf global $plugin latest
+done
+# Just add these, for now.
+asdf plugin add python
+
 if [ ! -d ~/.tmux/plugins/tpm ] ; then
   git clone https://github.com/tmux-plugins/tpm ~/.tmux/plugins/tpm
   if [ "$TMUX" != "" ] ; then