Add "report", "helpful" beside each comment

[liumcse]

Inappropriate comments should be brought to attention.

This feature is suggested by Nanyang Chronicle, the official NTU newspaper.

Log in is NOT required.

[chenchongsong]

Do we need to ask for reasons of reporting? If yes, we need a new MySQL Table to store all reporting reasons, otherwise we only need a new column in the original comment table.

All reported comments can be shown in django admin portal.

[liumcse]

Good question. We will also add helpful/unhelpful beside each comment. Deadline for these features is by the end of October.