Rewrote readLines function to be more concise

app/Main.hs

@@ -15,7 +15,7 @@ readLinesHelper xs = do
       readLinesHelper xs'
 
 readLines :: IO [String]
-readLines = fmap reverse $ readLinesHelper []
+readLines = reverse <$> readLinesHelper []
 
 main :: IO ()
 main = do