docs: update readme

README.md

@@ -1,2 +1,10 @@
 # docker_kimai
 
+this repo deploys kimai in a docker container
+
+HINT: for this version you need a dedicated mysql database! (e.g. mariadb)
+
+how to use:
+1. clone this repo via https to your server where you want to deploy kimai.
+2. go in the folder, start the setup script and follow the instructions.
+3. kimai should run now!