Merge pull request #11 from purescript/phil/10

Add MonadZero instance

Author: paf31

src/Data/Functor/App.purs

@@ -7,7 +7,7 @@ import Control.Alternative (class Alternative)
 import Control.Comonad (class Comonad)
 import Control.Extend (class Extend)
 import Control.Lazy (class Lazy)
-import Control.MonadPlus (class MonadPlus)
+import Control.MonadPlus (class MonadZero, class MonadPlus)
 import Control.Plus (class Plus)
 
 import Data.Eq (class Eq1, eq1)
@@ -58,6 +58,7 @@ derive newtype instance monadApp :: Monad f => Monad (App f)
 derive newtype instance altApp :: Alt f => Alt (App f)
 derive newtype instance plusApp :: Plus f => Plus (App f)
 derive newtype instance alternativeApp :: Alternative f => Alternative (App f)
+derive newtype instance monadZeroApp :: MonadZero f => MonadZero (App f)
 derive newtype instance monadPlusApp :: MonadPlus f => MonadPlus (App f)
 derive newtype instance lazyApp :: Lazy (f a) => Lazy (App f a)
 derive newtype instance foldableApp :: Foldable f => Foldable (App f)