give types to stack overflow questions

[kohlhase]

The questions (let's call the stack overflow questions forum posts for this discussion) should have a type according to the taxonomy Mihai and I talked about.
We have two different dimensions for forum posts:
global / local: global applies to the whole course, local will be for localized comments (i.e. hanging from a particular document). The global ones, could indeed be local to the course so maybe this is not a technical distinctinction. But local posts should have a link to their anchor (the element they are attached to).
announcement / question / issue: the announcement will be of a push character, all subscribers to the document will be notified. Questions probably behave similarly (but maybe you can opt out of subscriptions to questions separately). Authors will definitely be notified of Issue reports.

In the forum posts overview view (e.g. at http://panta.kwarc.info/stack-overflow/15), only the global ones should be visible (actually we should have a toggle for that) probably the different categories should be marked by different colors.

[kohlhase]

when we have the announcement / question / issue types, we may also want to differentiate the "ask a question" link to http://panta.kwarc.info/node/add/question?og_group_ref=15 on http://panta.kwarc.info/course-forum/15 into the types.