Wrong chapter for deployment

[algosuna]

Chapters 20 and 21 ("Extend your application" and "Django Forms") point the reader towards the end of chapter 15 for deployment info, while it is located in chapter 11.

I'm too lazy to do a pull request so I'm just leaving this here :)

[aniav]

I think the idea of pointing the reader to that chapter is to remind her where the information is. Do you think this is not correct? How we can improve that?

[algosuna]

yeah, but the deployment info is no longer in chapter 15, at least I didn't see it there....

[aniav]

Ah, you're right! Fixing that. Thank you! :)