Added ability to set an error code on the context in the event of failure
Thinking an options hash might be better in this instance, so that you can specify which is the message and which is the error. Just passing both in as a method call seems wonky, although just calling fail! with only a message (as usual) is still supported.
Merge pull request #35 from jenpayne/add_error_code_to_failure_context

Added ability to set an error code on the context in the event of failur...