Introduction of web/channels directory

[courtney]

Might be related to the updates to phoenix but "web" directory isn't installed by default. So the instructions reference this directory in the installfest but it doesn't yet exist 01_Installfest/10-deploy-a-phoenix-app.html.

[courtney]

Also might help to let folks know that the brunch commands need to be run from the assets directory on this page: /01_Installfest/11-deploy-to-heroku.html

[courtney]

also phoenix.server is deprecated. Use phx.server