added makefile config to have automatically the last commit in the title slide

Makefile

@@ -7,8 +7,9 @@ BEAMEROPTIONS += -V fontsize=smaller
 BEAMEROPTIONS += --highlight-style espresso
 BEAMEROPTIONS += -H ./header.tex --listings
 
+BLA = $(shell git log | head -n 1)
 
 default: git_tutorial.md
-	BLA=`git log | head -n 1`
+	echo $(BLA)
 	sed -i '3s/.*/% $(BLA)/' git_tutorial.md
 	pandoc -s $(BEAMEROPTIONS) -o git_tutorial.pdf git_tutorial.md