Add a thank you when post submitted

[codinghorror (Jeff Atwood)]

@Roman

Since we don’t queue posts, posting rules apply. You shouldn’t be able to post 50 times in a row.

We just need to make sure we have tested this scenario. 50 times in a row in one topic, or 50 times on 50 different topics.. rate limiting must apply, so people can’t blow up the review queue intentionally or accidentally.