add a minimal README

README.md

+
+# LCSB LaTeX beamer template
+
+This is a simple work-alike of the official LCSB slide templates, heavily
+inspired by the Metropolis theme.
+
+Clone this and type `make`, if your TeX distribution is okay, the example
+`slides.tex` should get compiled to `slides.pdf`.
+
+Proper documentation will be written once this gets used a bit and all rough
+edges are cleaned up; in the meantime it is likely better to just follow the
+example layouts in `slides.tex`.
+
+Open issues/send merge requests in case of any ideas.