Add generics functions to mongo class.

mongo.js

@@ -22,6 +22,22 @@ class Mongo {
             client.close();
         })
     }
+
+    insert(collectionName, entity, callback) {
+        this.db.collection(collectionName).insert(entity, (error, result) => {
+            assert.equal(null, error, `Unable to insert ${collectionName} entity: ${error}.`);
+            console.log(`Entity ${collectionName} inserted.`);
+            callback(result);
+        })
+    }
+
+    update(collectionName, entity, query, callback) {
+        this.db.collection(collectionName).update(query, entity, (error, result) => {
+            assert.equal(null, error, `Unable to update ${collectionName} entity: ${error}.`);
+            console.log(`Entity ${collectionName} updated.`);
+            callback(result);
+        })
+    }
 }
 
 module.exports = Mongo;