title: How can I prevent hacking like $remove in AngularFire
body: <p>All:</p>
  
  <p>I am pretty new to AngularFire, when I follow tutorial to do a simple todo app, I wonder how can I only allow user to add new todo, but not delete. Basically I do not want client side hack to destroy my data. Like user opens console and manually call $remove API, how can I prevent that?</p>
  
  <p>Thanks</p>