Create Instructions for resetting password locally

[falonofthetower]

Prevent the need for setting up email locally (or have a local email solution) so that developers know how to reset passwords on accounts locally

[rogerroelofs]

When we get auth in, you can use http://localhost:4000/dev/mailbox to see any emails your local app has 'sent'. I've updated the README to include a note about this.

[rogerroelofs]

@falonofthetower When you have a minute, look over the README and see if you think we can close this.