Create README.md

README.md

+minetest-caverealms
+===================
+
+A mod for Minetest to add underground realms
+
+For more information, view the official forum topic at:
+https://forum.minetest.net/viewtopic.php?f=9&t=9522
+
+Contributors:
+HeroOfTheWinds - everything
+
+Licensed under the WTFPL