Do some basic setup

app/Main.hs

@@ -1,6 +1,6 @@
 module Main where
 
-import Lib
+import Rextra.Rextra (rextra)
 
 main :: IO ()
-main = someFunc
+main = rextra

src/Lib.hs

@@ -1,6 +0,0 @@
-module Lib
-    ( someFunc
-    ) where
-
-someFunc :: IO ()
-someFunc = putStrLn "someFunc"

src/Rextra/Rextra.hs

@@ -0,0 +1,6 @@
+-- This file will be split up as it grows.
+module Rextra.Rextra where
+
+-- * Just a placeholder function
+rextra :: IO ()
+rextra = putStrLn "rextra"

stack.yaml.lock

@@ -0,0 +1,12 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages: []
+snapshots:
+- completed:
+    size: 524786
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/14/11.yaml
+    sha256: 088bb91b545839510a41ae92fa5feb36779ef3529571a42bd12b9f51eb89ded3
+  original: lts-14.11