Fix warnings.

Change-Id: I9e03d6110d2d9ee5f7cdaa540902e25ddb599ef7
diff --git a/src/Mulkup/Config.hs b/src/Mulkup/Config.hs
index 4be5b64..8356824 100644
--- a/src/Mulkup/Config.hs
+++ b/src/Mulkup/Config.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE UndecidableInstances #-}
 
 module Mulkup.Config (TierConfig (..), TierConfigs (..), StashConfig (..), MulkupConfig (..), readConfig) where
diff --git a/src/Mulkup/Flags.hs b/src/Mulkup/Flags.hs
index c5aa758..fd95b83 100644
--- a/src/Mulkup/Flags.hs
+++ b/src/Mulkup/Flags.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE UndecidableInstances #-}
 
 module Mulkup.Flags (Flags (..), flagParser) where
diff --git a/src/Mulkup/Ranking.hs b/src/Mulkup/Ranking.hs
index f162895..09397eb 100644
--- a/src/Mulkup/Ranking.hs
+++ b/src/Mulkup/Ranking.hs
@@ -55,7 +55,6 @@
   julianDay + fromIntegral (dayOfWeekDiff (dayOfWeek day) Sunday)
   where
     (ModifiedJulianDay julianDay) = day
-    dayOfWeekDiff a b = mod (fromEnum a - fromEnum b) 7
 
 utctMonth :: UTCTime -> Integer
 utctMonth (UTCTime day _) = fromIntegral m