Changed aakashuser/models.py and askquestion template

1. Added select category option in ask a question.
2. Added an extra ForeignKey field (Category) category in Post model.
3. Linked with no. of related posts to categories.
Ajax UpVote/DownVote implemented

1. UpVote/DownVote unique to a User
2. Bugs yet to be fixed
3. Post model changed (2 fields added, 1 deleted)
Dummy Commit #1

> Refer prev. Commit
sample commit#1
Merge remote-tracking branch 'upstream/master'

Conflicts:
	ac/views.py
	db.sqlite3
resolved conflicts in ac/views.py