Use sudo to permit --system gem updates

zsh/aliases

@@ -40,6 +40,10 @@ function update() {
     brew update
     brew upgrade
     
+    # Keep sudo alive
+    sudo -v
+    while true; do sudo -n true; sleep 60; kill -0 "$$" || exit; done 2>/dev/null &
+
     # Make sure rvm is sourced properly
     if [ -f ~/.rvm/scripts/rvm ]; then
         [ "$(type -t rvm)" = "function" ] || source ~/.rvm/scripts/rvm