add new files

api/controllers/groupController.js

@@ -0,0 +1,23 @@
+'use strict';
+
+var mongoose = require('mongoose'),
+Group = mongoose.model('Group');
+
+exports.list_all = function(req, res) {
+    Group.find({}, function(err, group) {
+    if (err) {
+        res.send(err);
+    }
+    res.json(group);
+  });
+};
+
+exports.add_group = function(req, res) {
+    var new_group = new Group(req.body);
+    new_group.save(function(err, group) {
+        if (err) {
+            res.send(err);
+        }
+        res.json(group);
+    });
+};