a cask plugin ( see robbyrussell/oh-my-zsh#1999 )

home/.zsh/custom/plugins/cask/cask.plugin.zsh

@@ -0,0 +1,6 @@
+if [ -d $HOME/.cask ]; then
+  export PATH="$HOME/.cask/bin:$PATH"
+fi
+if which cask &> /dev/null; then
+  source $(dirname $(which cask))/../etc/cask_completion.zsh
+fi