Add a Makefile

We can make things easier on contributors if we setup a build system.
We can also make CI easier if we use Make.

.gitignore

@@ -1,6 +1,8 @@
 ### Project specific ###
 
 *.cabal
+.make
+bin
 
 # Created by https://www.gitignore.io/api/vim,osx,linux,macos,emacs,windows,haskell,visualstudiocode
 

Makefile

@@ -0,0 +1,35 @@
+BIN := bin
+EMPTY := .make
+GHCID := $(BIN)/ghcid
+STACK := stack
+STACK_WORK := .stack-work
+
+.DEFAULT_GOAL := build
+
+$(EMPTY):
+	mkdir $@
+
+$(EMPTY)/stack-setup: | $(EMPTY)
+	$(STACK) setup
+	touch $@
+
+$(GHCID): $(EMPTY)/stack-setup
+	$(STACK) install ghcid --local-bin-path $(BIN)
+
+.PHONY: build
+build: $(EMPTY)/stack-setup
+	$(STACK) build --no-run-tests --test
+
+.PHONY: clean
+clean:
+	rm -f $(BIN)/*
+	rm -f $(EMPTY)/*
+	rm -fr $(STACK_WORK)
+
+.PHONY: test
+test: build
+	$(STACK) test
+
+.PHONY: watch
+watch: $(GHCID)
+	$(GHCID)