Able to set Docker network and custom hosts during build

[andrasbacsai]

Feature request

Simply able to set custom docker network (--network) and add hosts (--add-host) to the nixpacks command, so the build process will have access to the internal resources - and in case of a user defined network - and dns.

Motivation

For example, if you build a NodeJS based project with Prisma(prisma.io), the build process is not able to access the database to generate types for the final image.

Contribution

I can help with more details, or even submit a PR.

[brody192]

Railway does want to make the builder a part of the private network at some point, when that happens there would be no need for any of these configurations!!

[JakeCooper]

Would defs take a PR for this!