Add Developer Section / How to Contribute from cwiki.apache.org
Add Developer Section / How to Contribute from cwiki.apache.org

Reviewers: Attila Simon

This closes #79

tinawenqiao/flume,iaiengxia/flume,tmgstevens/flume,szaboferee/flume,szaboferee/flume,szaboferee/flume,tmgstevens/flume,iaiengxia/flume,iaiengxia/flume,tinawenqiao/flume,iaiengxia/flume,tinawenqiao/flume,tmgstevens/flume,tinawenqiao/flume,szaboferee/flume,tmgstevens/flume