Added basic month/year filtering to stockings

This has a failing test.  I'm opening the pull request to discuss it.  I've added a select to the page and its onchange fires javascript to submit the form.  However, I don't think rspec understands this and so it may not be waiting for the page to reload before looking for last month's stocking.  Thoughts?
This line fails.  I'm assuming rspec is not waiting for page reload before doing this check.