chore: add demo script to Makefile

To run demo, run `make demo`.

Makefile

@@ -21,3 +21,30 @@ build: fmt
 
 install: build
 	cp bin/$(APP_NAME) /usr/local/bin/$(APP_NAME)
+
+demo: demo-prepare demo-exec
+
+demo-prepare:
+	-rm -rf /tmp/git-remind-demo
+	mkdir -p /tmp/git-remind-demo
+	cd /tmp/git-remind-demo && \
+	git init myapp1 && \
+	git init --bare myapp2-origin.git && \
+	git clone /tmp/git-remind-demo/myapp2-origin.git myapp2 && \
+	git init myapp3 && \
+	cd /tmp/git-remind-demo/myapp1 && \
+	touch unstaged-file
+	cd /tmp/git-remind-demo/myapp2 && \
+	git commit --allow-empty -m commit1 && \
+	git push && \
+	git commit --allow-empty -m commit2
+
+demo-exec:
+	@echo
+	@echo "==== D E M O ===="
+	@echo
+	@set -eux && \
+	export GIT_REMIND_PATHS='/tmp/git-remind-demo/*' && \
+	git-remind paths && \
+	git-remind status -a && \
+	git-remind status-notification