serving/helloworld-haskell: respect the port env var (#463)

Author: grayside

serving/samples/helloworld-haskell/README.md

@@ -63,9 +63,11 @@ following instructions recreate the source files from this folder.
 	import           Web.Scotty.Trans
 
 	main :: IO ()
-	main = do
-      t <- fromMaybe "World" <$> lookupEnv "TARGET"
-      scotty 8080 (route t)
+  main = do
+    t <- fromMaybe "World" <$> lookupEnv "TARGET"
+    pStr <- fromMaybe "8080" <$> lookupEnv "PORT"
+    let p = read pStr :: Int
+    scotty p (route t)
 
 	route :: String -> ScottyM()
 	route t = get "/" $ hello t

serving/samples/helloworld-haskell/app/Main.hs

@@ -11,7 +11,9 @@ import           Web.Scotty.Trans
 main :: IO ()
 main = do
   t <- fromMaybe "World" <$> lookupEnv "TARGET"
-  scotty 8080 (route t)
+  pStr <- fromMaybe "8080" <$> lookupEnv "PORT"
+  let p = read pStr :: Int
+  scotty p (route t)
 
 route :: String -> ScottyM()
 route t = get "/" $ hello t