Add post-build script

[vbrandl]

I like to compress my hugo output ahead of time to prevent the webserver from compressing the files on the fly on each request.

I do this using a Makefile. It would be cool to have a parameter for this plugin to execute custom commands after the hugo build has finished.

[tboerger]

Really no need to integrate that into the Hugo plugin, just add another step to your drone pipeline.

[vbrandl]

Oh yeah, you are right. That's actually the nicer way. Thanks.