[ticket/998] Add a readme.MD

http://www.flying-bits.org/tracker.php?p=33&t=998

Preview @ https://github.com/Un1matr1x/phpbb3-mod-newspage/tree/ticket/998

Note that README.md is already mentioned @ https://github.com/nickvergessen/phpbb3-mod-newspage/blob/master/.gitattributes#L3 to not be exportet on download