When you say “Add a migration and a field…”
At this point, you haven’t actually explained how one might go about adding a migration. So those of us that are familiar with Ecto and how to do migrations will be able to work this out. However, those that aren’t are likely to be completely stuck. As this is a book about Liveview, not necessarily Ecto, I can’t see how this exercise really helps with learning Liveview
Thanks for sharing your thoughts and feedback here 
It’s true that those who have never worked with Ecto may not know exactly where to start with adding a migration. There are some (generated) examples in this chapter that will hopefully help, and a Google search would also turn up lots of resources on the topic of adding a migration to a Phoenix app.
Our intention with this exercise is to give readers a chance to really build Phoenix LiveView apps from the ground up. It’s true that adding a migration isn’t a LiveView-specific exercise, but if you’re building a LiveView app in the wild, you will find yourself needing to complete exactly this task.
