Clearly suggest to run latest

README.md

@@ -14,5 +14,5 @@ docker run \
   -e MINECRAFT_VERSION=1.10 \
   -v /home/user/minecraft/:/home/minecraft/server/:ro \
   -v /srv/http/minecraft/:/home/minecraft/render/:rw \
-  mide/minecraft-overviewer
+  mide/minecraft-overviewer:latest
 ```