Catch RecordNotFound exception

app/assets/javascripts/app.js

@@ -0,0 +1 @@
+window.ENSL = Ember.Application.Create();

app/controllers/application_controller.rb

@@ -50,6 +50,10 @@ class ApplicationController < ActionController::Base
     render text: t(:application_stale)
   end
 
+  rescue_from ActiveRecord::RecordNotFound do |exception|
+    render :template => 'errors/404.html', :status => :not_found, :layout => 'errors'
+  end
+
   private
 
   def update_user

public/404.html

@@ -0,0 +1,2 @@
+<h1>The page you were looking for doesn't exist.</h1>
+<p>You may have mistyped the address or the page may have moved.</p>