add confirmation for destroying list
add Task model
add tasks_controller, update routes, add task model test file
db/seeds
add has_many :tasks to List
fix Task#list_id
fix Task belongs_to :list
update ListSerializer
add TaskSerializer
add list_id to TaskSerializer
add Task.js Em model
update List.js Em model
make List serializer works with Ember weird convention for JSON nesting
output sample tasks in list