Update README.md

Link SecureDrop.org repository instead of website

README.md

@@ -318,7 +318,7 @@ Awesome Wagtail [![Awesome](https://cdn.rawgit.com/sindresorhus/awesome/d7305f38
 - [RTEI](https://github.com/okfn/rtei) – Right to Education Index website (OKFN).
 - [BVSPCA](https://github.com/nfletton/bvspca) – Bow Valley SPCA website.
 - [Project TIER](https://github.com/ProjectTIER/projecttier.org) – Teaching Integrity in Empirical Research.
-- [SecureDrop](https://securedrop.org/) – Wagtail-powered website of the SecureDrop whistleblower document submission system.
+- [SecureDrop](https://github.com/freedomofpress/securedrop.org) – Wagtail-powered website of the SecureDrop whistleblower document submission system.
 
 ## Contribute