Support for multiproject builds with nix

- Closes #28

backend/src/Types.hs

@@ -0,0 +1,24 @@
+{-# Language NoImplicitPrelude #-}
+{-# Language DeriveGeneric #-}
+{-# Language TypeSynonymInstances #-}
+{-# Language FlexibleInstances #-}
+module Types
+  ( App(..)
+  , AppM
+  -- Figure out how to re-export instances
+  ) where
+
+import ClassyPrelude
+import Control.Monad.Logger
+import Configuration
+import Data.Pool (Pool)
+import Database.Selda.Backend (SeldaConnection)
+import Servant.Auth.Server as SAS ()
+import Crypto.JOSE.JWK (JWK)
+
+data App = App { config :: Config
+               , database :: Pool SeldaConnection
+               , jwk :: JWK }
+         deriving (Generic)
+
+type AppM = LoggingT (ReaderT App IO)