Document running live-serer better

[drorm]

Please make explicit that you run live-server in the root dir, but go to hostname:8080/app. The paths are wrong if you to run liveserver in the app dir.

Also, no need to install live-server -g. You can just do
./node_modules/.bin/live-server

[topherfangio]

We've updated the tutorial to use live-server --open=app as well as adding some additional docs to account for this issue.

Thanks for pointing it out!