update based on feedback

server/middleware/check-client-version.js

@@ -0,0 +1,12 @@
+module.exports = (req, res, next)=>{
+	const userVersion = req.get('Homebrewery-Version');
+	const version = require('../../package.json').version;
+
+	if(userVersion != version) {
+		return res.status(412).send({
+			message : `Client version ${userVersion} is out of date. Please save your changes elsewhere and refresh to pick up client version ${version}.`
+		});
+	}
+
+	next();
+};