fastcgi cache purge fails if not using trailing slashes in URI structure

This was kind of an annoying bug, wasn’t sure why purge on save wasn’t working. I could purge it manually with example.com/purge/foo, but saving the post didn’t purge the cache. The nginx-helper log kept showing it was trying to purge example.com/purge/foo/ and then saying there was nothing to purge.

I added the following rewrite to my server config and it works now:
rewrite ^/purge(/.*)/$ /purge$1 permanent;

This should either be documented in the installation FAQ, or ideally updated in the plugin so that purging works with both trailing and non-trailing slashes…