create firebase app ref
initialize firebase auth service
move script to external app.js
ref to app.js
add sign in button
add angularjs
convert js to angularjs
set up firebase constant values
login with facebook
move script code to app.js
implemented sign out
setup karma test runner
add angular-mock
create FirebaseUser service to store signed in user
add multiple callbacks support for User.onChange
add underscore
added sinon
added underscore
change FirebaseUser to User
hide sign in button when user has logged in