Watch / follow a package

[rgrp]

As a (logged-in) User I want to watch (follow) a package, that is register my interest about a package. (Similar to watch/follow features in github/bitbucket/wikis).

NB: this is as much (if not more) about showing what packages are interesting to people as giving info to 'watchers'.

TODO: finalize terminology (github uses watch for repos and follow for users while bitbucket combines both in 'followers').

Implementation

Become watcher:

• Watch button on packages (if already watching say 'Unwatch')

Package-related changes:

• Show number of watchers on a package
• List number of watchers of a package
  • On a separate page (a la github) or on the main page (more like bitbucket overview)

User-related changes:

• Show what packages a user has started/stopped followed on a user's public activity stream on their user page
• List watched packages
  • Either on user's page on a separate 'following' page. (NB: called 'following')
• Does watching involve notifications (by email)
  • Probably not: you can already subscribe to RSS feed after all and email not that necessary (?)

Random Extras

• What about following users as well