text: 		
  // In the first few sections, we do all the coding here.
  // Later, you'll see how to organize your code into separate
  // files and modules.
  
  var Vehicle = Backbone.Model.extend({
  
  	idAttribute: "registrationNumber",
  
  	urlRoot: "/api/vehicles",
  
  	validate: function(attrs){
  		if (!attrs.registrationNumber)
  			return "Vehicle is not valid.";
  	},
  
  	start: function(){
  		console.log("Vehicle started.");
  	}
  });
  
  var Vehicles = Backbone.Collection.extend({
  	Model: Vehicle
  });
  
  var Car = Vehicle.extend({
  	start: function(){
  		console.log("Car with registration number " + this.get("registrationNumber") + " started.");
  	}
  });
  
  var vehicles = new Vehicles([
  	new Car({ registrationNumber: "XLI887", color: "Blue" }),
  	new Car({ registrationNumber: "ZNP123", color: "Blue" }),
  	new Car({ registrationNumber: "XUV456", color: "Gray" })
  ]);
  
  var blueCars = vehicles.where({ color: "Blue" });
  console.log("Blue cars", blueCars);
  
  var carXLI887 = vehicles.findWhere({ registrationNumber: "XLI887" });
  console.log("Car with registration number XLI887", carXLI887);
  
  vehicles.remove(carXLI887);
  
  console.log("Vehicles as JSON", vehicles.toJSON());
  