Add ability to target merge to alternate branch

[segiddins]

patronus: test => branch
patronus: :+1: => branch

Thoughts?

[chalkos]

Using :+1:, if the test passes, should the PR be merged to a different branch? O_o

[segiddins]

Yeah, that'd be the idea.

[chalkos]

That sounds strange to me (and I'm not even talking about the technical difficulties, like non-fastforwardable changes)... if the PR was opened to the wrong branch, one could just close it and open one to the correct branch, leaving a comment so someone else may follow the trail...

changing the target branch of a PR seems like something that github could implement (see isaacs/github#18), and not something for Patronus to do (unless you want to automate the closing-branch-and-opening-new-one part).

[segiddins]

The problem is that you lose all the context & discussion on the PR, in addition to making more work for drive-by contributors

[chalkos]

I think it would be more confusing to drive-by contributors to see a PR from chalkos:bf-some-branch to patronus-io:master and then find out that the PR was closed without being merged and there is a message that seems to indicate that the PR was merged to patronus-io:dev instead (although github identifies the target as patronus-io:master).

A comment/description like "Wrong target branch, sorry. See #... for the correct pull request." would require an extra click from the reader, but would be less confusing IMO.