include link to "login" in /users error msg. when visitor attempts to sign w/ registered email

[davidmooreppf]

If visitor hits Q page and attempts to sign the Q, with an email that's already been registered, app directs to /users (not /users/sign_up) and displays error "this email has already been taken".

From that page, the only place there for user to login is at far bottom of page, "log in".

In these cases, can we include the link to /users/sign_in in the error message, where it reads 2 errors prohibited this user from being saved:?

Ideal is: Email is already taken, please login.

Then, there's probably not a way to get them back to the referring Q page, is there. They'll bounce to homepage. Well, that's a step forward.