Heroku integration with foreman

Add foreman configuration for Heroku:
- To test production configuration execute NODE_ENV=production foreman
  start
- Database connection configuration now handles "use_env_variable" which
  should be defined as a environment variable such as "DATABASE_URL"
  with a proper database URI connection string, ie:
  postgres://user:password@db.example.com:5432/database
- Added package.json configuration to run migrations and db seed after
  `npm install`

Update frontend models to match sequelize definition.
Update views to work according to the changes above.
Handling isCompleted and parentId apropiately for PostgreSQL databases

server.js

@@ -29,7 +29,7 @@ app.get('/tasks', function(req,res){
 app.post('/tasks', function(req,res){
   Tasks.create({
     content: req.body.content,
-    parent: req.body.parent_id,
+    parent: parseInt(req.body.parent_id) || 0,
     isCompleted: false
   }).success(function(task){
     res.send(task);
@@ -40,7 +40,7 @@ app.put('/tasks/:id', function(req,res){
   console.log(req.body.isCompleted);
   Tasks.find(req.params.id).success(function(task){
     task.content = req.body.content;
-    task.isCompleted = req.body.isCompleted;
+    task.isCompleted = req.body.isCompleted == 1;
     task.save().success(function(task){
       res.send(task);
     })