Automatic merge of Pull Requests

I've seen that you can do automatic merges of feature branches, however, I want to have the merge happen after the pull request merge testing has taken place, per the instructions here:

https://blog.jetbrains.com/teamcity/2013/02/automatically-building-pull-requests-from-github-with-teamcity/

In theory, this would mean that master should never have any failing tests.

Is there a way to get this to work through the automatic merge feature?  Or do I need to manually perform the pull request merge via curl'ing and api call?