Notifications

[jmatsushita]

See http://iilab.github.io/contentascode/technology/workflow/#notifications
Related to #43

Some of the use cases for this would be:

• I browse, see an interesting page and want to be notified when content on a particular page changes.
• There are "area of interests" on the site which I can join.
• Allow users to watch a particular page
• Allow users to watch an issue

Areas of interest could be mapped to a folder or subrepo if they are clearly mapped to the site content structure, or could be mapped to grouping of issues if they have their own logic (like project management, or a categorisation that's somewhat orthogonal from content):

• Allow users to watch a section (folder or subrepo)
• Allow users to watch a grouping of issues (tags, milestone,...)

UPDATE: Moving notes to the issue tracker integration issue #40

[jmatsushita]

Another moving part for notifications is the new possibility to create groups and @mention them with Github (and being worked on for Gitlab https://gitlab.com/gitlab-org/gitlab-ce/issues/4309).