Add WTB/WTS buttons

[nathang15]

Describe Issue

Currently, when users want to post, they have to include either a #wtb (for want to buy) or #wts (for want to post). We wish to add 2 buttons for users to select what type of post it will be (a sell or a buy post).

Describe preferred solution

Add a button or buttons in the UI that will directly add the tag onto the post form when clicked upon. Noted that the buttons can only be clicked once. If clicked again, the tag will disappear and the button can now be clicked.

Additional Information

Will need further discussion on this issue.