1 files changed, 11 insertions, 4 deletions

diff --git a/server/src/Thermoprint/Server/Database.hs b/server/src/Thermoprint/Server/Database.hs
index 1e01680..5bd4512 100644
--- a/server/src/Thermoprint/Server/Database.hs
+++ b/server/src/Thermoprint/Server/Database.hs
@@ -4,6 +4,7 @@
 {-# LANGUAGE TypeFamilies               #-}
 {-# LANGUAGE ExistentialQuantification  #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE StandaloneDeriving         #-}
 {-# LANGUAGE FlexibleInstances          #-}
 
 module Thermoprint.Server.Database
@@ -11,7 +12,6 @@ module Thermoprint.Server.Database
        , Draft(..), DraftId
        , Key(..)
        , migrateAll
-       , castId'
        ) where
 
 import Control.DeepSeq
@@ -32,8 +32,15 @@ Draft
     content Printout
 |]
 
+deriving instance Enum     (Key Job)
+deriving instance Num      (Key Job)
+deriving instance Real     (Key Job)
+deriving instance Integral (Key Job)
+
+deriving instance Enum     (Key Draft)
+deriving instance Num      (Key Draft)
+deriving instance Real     (Key Draft)
+deriving instance Integral (Key Draft)
+
 instance NFData (Key Job) where
   rnf = rnf . unSqlBackendKey . unJobKey
-
-castId' :: Enum b => BackendKey SqlBackend -> b
-castId' = castId . unSqlBackendKey