When using Dockerfiles, each build step is not cached. This looks to be by design:
9a71fff

Is there a way of allowing the occasional forcing of fresh builds without disabling caching for every build step ?

My particular use-case is shown here, where the package restore is rather slow and mostly the same each time:
aspnet/aspnet-docker#59

Maybe Dokku could include a http proxy for this kind of thing ? Or a cache volume could be attached automatically ?