Add Add Chris' key to list of merge keys.
Add Add Chris' key to list of merge keys.

So that he can merge PRs against this repo.

alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf