add documentation on how to check if a user is authenticated

src/libs/middlewares/passport.js

@@ -9,7 +9,7 @@ module.exports = function(passport){
     opts.jwtFromRequest = ExtractJwt.fromAuthHeader();
     opts.secretOrKey = config.get('mongodb:secret');
     passport.use(new JwtStrategy(opts, function(jwt_payload, done){
-        User.find({id: jwt_payload.id}, function(err, user){
+        User.find({email: jwt_payload.email}, function(err, user){
             if (err) {
                 return done(err);
             }
@@ -22,3 +22,29 @@ module.exports = function(passport){
         });
     }));
 };
+
+/* To check if a user has access to a route, one must use passport.authenticate() specifying 'JWT' as the strategy in the route declaration, like so:
+app.post('/route', passport.authenticate('jwt', { session: false}), function(req, res) { });
+
+the user object is then accessible via req.user
+----
+
+Another way to check if a user is authenticated, is to check the request header for the json web token, like so:
+
+getToken = function (headers) {
+  if (headers && headers.authorization) {
+    var parted = headers.authorization.split(' ');
+    if (parted.length === 2) {
+      return parted[1];
+    } else {
+      return null;
+    }
+  } else {
+    return null;
+  }
+};
+
+var token = getToken(req.headers);
+  if (token) {
+    var decoded = jwt.decode(token, config.get(mongodb.secret));
+  }