Add bin/update script

bin/update

@@ -0,0 +1,27 @@
+#!/bin/zsh
+
+brew update && brew upgrade --all
+cd "$HOME/.emacs.d" && git pull && make
+cd "$HOME/.dotfiles" && git pull
+
+local i
+if [ -d ~/.rbenv ]; then
+    cd "$HOME/.rbenv" && git pull
+    for i in "$HOME"/.rbenv/plugins/*; do
+        cd "$i" && git pull
+    done
+fi
+
+if [ -d ~/.pyenv ]; then
+    cd "$HOME/.pyenv" && git pull
+    for i in "$HOME"/.pyenv/plugins/*; do
+        cd "$i" && git pull
+    done
+fi
+
+if [ -d ~/.zprezto ]; then
+    cd "$HOME/.zprezto"
+    git fetch parent
+    git submodule foreach git checkout master
+    git submodule foreach git pull
+fi