update donation

README.md

@@ -9,6 +9,9 @@ Download from github.io: [Centos6-x86_64][centos0], [more...][more0]<br/>
 Download from ossrs.net: [Centos6-x86_64][centos1], [more...][more1]<br/>
 Website for SRS/1.0, read SRS 1.0 [Chinese][srs1_CN] or [English][srs1_EN].
 
+[![Donation](https://www.paypalobjects.com/webstatic/en_US/btn/btn_donate_92x26.png)](http://www.ossrs.net/srs.release/donation/index.html)
+[![Paypal](https://www.paypalobjects.com/webstatic/en_US/btn/btn_donate_pp_142x27.png)](http://www.ossrs.net/srs.release/donation/paypal.html)
+
 ## About
 
 SRS(SIMPLE RTMP Server) over state-threads created in 2013.10.