Dynamic login message - Welcome Back / You've Signed Up

[mmwtsn]

Need to update the notification for when a user signs up for a campaign and when a user returns to a campaign they are already signed up for.

Notification messages should look like this:
https://s3.amazonaws.com/uploads.hipchat.com/34218/407723/jn8yiKwQ2EQROAt/Action%20Page%20Notification.pdf

[aaronschachter]

Discussion with @mikefantini today:

Desired behavior for "Welcome back" message is any time a user logs in, NOT any time they return to a campaign node. Ideally this should check whether or not the user is new, or for us to count number of logins (or at least set a field/flag for "returning user"), so you don't get "welcome back" upon your first login.

Need to investigate the one scenario where a user logs in via pitch page, and not displaying both messages.

[mikefantini]

Yeah it's for any time a user logs in, unless they are logging in to sign up for a campaign for the first time of that campaign's current run.

Then they should get the "You're signed up" notification.

[aaronschachter]

The campaign signup message has been completed in #992, so updating the issue title per what's left to build for this.

Per discussion with @mikefantini, the dynamic sign-in message that says "Welcome back" per comments above is not needed for 0.2 Moving this to backlog.