[task/github-readme] Add README file for GitHub

PHPBB3-9788

README.md

@@ -0,0 +1,20 @@
+[![phpBB](http://www.phpbb.com/theme/images/logos/blue/160x52.png)](http://www.phpbb.com)
+
+## ABOUT
+
+phpBB is a free bulletin board written in PHP.
+
+## COMMUNITY
+
+Find support and lots more on [phpBB.com](http://www.phpbb.com)! Discuss the development on [area51](http://area51.phpbb.com/phpBB/index.php).
+
+## CONTRIBUTE
+
+1. [Create an account on phpBB.com](http://www.phpbb.com/community/ucp.php?mode=register)
+2. [Create a ticket (unless there already is one)](http://tracker.phpbb.com/secure/CreateIssue!default.jspa)
+3. [Read our Git Contribution Guidelines](http://wiki.phpbb.com/Git); if you're new to git, also read [the introduction guide](http://wiki.phpbb.com/display/DEV/Working+with+Git)
+4. Send us a pull request
+
+## LICENSE
+
+[GNU General Public License v2](http://opensource.org/licenses/gpl-2.0.php)