Add pre-commit hook that enforces ormolu formatting

pre-commit

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+
+
+tmp=$(mktemp)
+
+
+find src/ -type f | while read f; do
+    if ! ormolu --mode check "$f"; then
+        echo "$f is not properly formatted"
+        echo 1 > "$tmp"
+    fi
+done
+
+
+if test "X1" = "X$(cat "$tmp")"; then
+    exit 1
+fi

src/Main.hs

@@ -2,11 +2,11 @@
 {-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE OverloadedStrings #-}
 
-import Protolude hiding (for)
-import Pretty
-import WS19
 import Pipes
+import Pretty
+import Protolude hiding (for)
 import System.IO
+import WS19
 
 mkPop = population 100 (I prios [])
 

src/Pretty.hs

@@ -1,11 +1,8 @@
 {-# LANGUAGE NoImplicitPrelude #-}
 
-
 module Pretty where
 
-
 import Protolude
 
-
 class Pretty a where
   pretty :: a -> Text

src/Test.hs

@@ -2,9 +2,9 @@
 
 module Main where
 
+import qualified GA
 import Protolude
 import qualified Seminar
-import qualified GA
 
 main :: IO ()
 main = do