Added starter setup script

bin/setup

@@ -0,0 +1,26 @@
+#! /bin/bash
+
+# Node installed?
+if ! [ -x "$(command -v node)" ]; then
+  echo 'Error: node is not installed.' >&2
+
+  if ! [ -x "$(command -v brew)" ]; then
+    echo 'Go here to install: https://nodejs.org/en/download/'
+  fi
+
+  if [ -x "$(command -v brew)" ]; then
+    echo 'You have Homebrew installed, so run "brew install node".'
+  fi
+
+  exit 1
+fi
+
+# React Native installed?
+if ! [ -x "$(command -v react-native)" ]; then
+  echo 'Error: React Native is not installed.' >&2
+  echo 'Go here: https://facebook.github.io/react-native/docs/getting-started.html' >&2
+  echo 'Use the "Building Projects With Native Code" option.'
+  exit 1
+fi
+
+# TODO: Automate setup on new machines