* Use alpine as the base image
* Parallelize bundle install
Using alpine as base make is feasable to use the provides vips library.
The version is actually newer than what was installed previously.
Other stuff I did:
* Set SECRET_TOKEN/SESSION_SECRET_KEY from docker-compose
* Mute elasticsearch startup logspam
* Execute image as root. This means mounted volume do'nt need to be chowned
* Reduces the image size by using alpine and cleaning up after some things
* Simplify the initial setup instructions slightly
* Access via localhost:3000 instead of e621.local
