Only run npm install on first boot

It's probably not the worst developer experience to restart the server
when adding new dependencies.

Author: madnificent

boot.sh

@@ -1,4 +1,7 @@
 #! /bin/sh
+## Install new dependencies
+npm install
+
 ./node_modules/supervisor/lib/cli-wrapper.js \
     -w /usr/src/app,/app \
     -i /usr/src/app/node_modules,/usr/src/app/helpers,/app/node_modules \

start.sh

@@ -3,8 +3,5 @@
 ## Kill lingering processes
 ps aux | grep babel-node | awk '{print $1}' | xargs kill -9
 
-## Install new dependencies
-npm install
-
 ## Run using babel
 NODE_PATH=`pwd`/node_modules:`pwd`/helpers:$NODE_PATH ./node_modules/babel-cli/bin/babel-node.js app.js --presets es2015,es2016,es2017