Subscription Model

[rgoraya]

Users can subscribe to Issues and receive (email) notifications about the addition/deletion of Relationships and References to these issues.

[rgoraya]

Detailed description by @badgerProd:
Add a "Follow" button to every Issue page and every relationship page, which, when clicked, causes the person to get emailed whenever anyone changes anything on the page. For example, if I am following an issue page, if anyone adds or removes any kind of relationship, I should get an email. If I am following a relationship, if anyone adds a reference, comments, endorses, contests, or removes the relationship, I get an email. (We may want to have check boxes of some sort, so you don't have to get an email for endorses/contestations, but that could potentially wait for later.) In order to follow something, you need to have a confirmed email address; if you don't, and you click follow, it will ask you to enter and confirm your email address.