hie.yaml for hadrian?

Motivation

IDEs ease a programmer's life; unfortunately configuring haskell-ide-engine (hie) for GHC and it's sub-projects takes some time. To simplify this process, I'd like to propose to add a hie.yaml file to Hadrian.

I know that adding tool-specific files to a project is not a "best practice", but I think because hie is meant to be the haskell ide tool, one could make an exception from this rule.

Proposal

Add a hie.yaml file to Hadrian's root folder.

My "quick & dirty" solution looks like this:

cradle:
  direct:
    arguments:
      - -isrc
      - -XDeriveFunctor
      - -XDeriveGeneric
      - -XFlexibleInstances
      - -XGeneralizedNewtypeDeriving
      - -XLambdaCase
      - -XRecordWildCards
      - -XScopedTypeVariables
      - -XTupleSections
      - -XMultiParamTypeClasses
      - -XTypeFamilies

It seems to work, though I haven't tested it thoroughly. (Only tried it for the Development.hs flavour, there it works fine.)