title: Adding additional metrics to Dropwizard
body: <p>How do I go about adding custom metrics to the default stuff that Dropwizard provides on the admin port (8081)?  I can't find anything in the documentation apart from adding health checks.  I'd quite like to incorporate some stats retrieved from MongoDB, and would rather keep it with the admin resources on 8081 than create a custom metrics page on port 8080.</p>