Automatically inject hash as version

Makefile

@@ -5,7 +5,14 @@
 #
 # Kitsune Scientific 2021
 
-all: generate
+hash := $(shell git rev-parse --short HEAD)
 
-generate: *.md
-	pandoc *.md -t beamer -o changeme.pdf
+all: generate clean
+
+generate: example_slides.md
+	cp example_slides.md working.md
+	sed -i "s/&hash/$(hash)/" working.md
+	pandoc working.md -t beamer -o changeme.pdf
+
+clean: working.md
+	rm working.md