Added clusters for zero-downtime.

mongoose auto-reconnect set to true.

app.js

@@ -1,7 +1,6 @@
 /**
  * Module dependencies.
  */
-var domain = require('domain');
 var express = require('express');
 var fs = require('fs');
 var flash = require('connect-flash');
@@ -26,7 +25,24 @@ var contactController = require('./controllers/contact');
 var secrets = require('./config/secrets');
 var passportConf = require('./config/passport');
 
-mongoose.connect(secrets.db);
+if (cluster.isMaster) {
+  var numCPUs = require('os').cpus().length;
+
+  for (var i = 0; i < numCPUs; i++) {
+    cluster.fork();
+  }
+
+  cluster.on('disconnect', function(worker, code, signal) {
+    console.error('worker ' + worker.process.pid + ' died');
+    cluster.fork();
+  });
+} else {
+
+  /**
+   * Connect to MongoDB.
+   */
+  var opts = { server: { auto_reconnect: true } };
+  mongoose.connect(secrets.db, opts);
 
   var app = express();
 
@@ -104,4 +120,4 @@ app.get('/auth/tumblr/callback', passport.authorize('tumblr', { failureRedirect:
   app.listen(app.get('port'), function() {
     console.log('Express server listening on port ' + app.get('port'));
   });
-
+}