Write the base commit to .git/base_sha

This is useful for when we need to know the SHA-1 of the base branch when the build ran which isn't necessarily the HEAD of `master` (or whatever the base branch is).

Author: aconrad

assets/lib/commands/in.rb

@@ -32,6 +32,7 @@ def output
         File.write('body', pr['body'])
         File.write('branch', pr['head']['ref'])
         File.write('base_branch', pr['base']['ref'])
+        File.write('base_sha', pr['base']['sha'])
         File.write('userlogin', pr['user']['login'])
         File.write('head_sha', pr['head']['sha'])
       end