a more robust merge script

When we can't look up a user's name or email the script fails. This will cause
it to default to the user's login.

Author: @sprsquish
Fixes #375
URL: #375

bin/git-pull-request.rb

@@ -207,7 +207,9 @@ def merge(number)
       user_login = pull_request['user']['login']
       user_obj = Github.get("users/#{user_login}")
       user_name = user_obj['name']
+      user_name = user_login if user_name.nil? || user_name.empty?
       user_email = user_obj['email']
+      user_email = user_login if user_email.nil? || user_email.empty?
 
       puts "Committing"
       Git.commit("--author=\"#{user_name} <#{user_email}>\" -m #{Shellwords.escape(commit_msg)} -e")