fix dead link to db* CODECOP tool suite

Author: PhilippSalvisberg

docs/index.md

@@ -48,7 +48,7 @@ The authors and publisher shall have neither liability nor responsibility to any
 
 ## Revision History
 
-The first version of these guidelines was compiled by Roger Troller on March 17, 2009. Jörn Kulessa, Daniela Reiner, Richard Bushnell, Andreas Flubacher and Thomas Mauch helped Roger complete version 1.2 until August 21, 2009. This was the first GA version. The handy printed version in A5 format was distributed free of charge at the DOAG Annual Conference and on other occasions. Since then Roger updated the guidelines regularily. Philipp Salvisberg was involved in the review process for version 3.0 which was a major update. Philipp took the lead, after Roger left Trivadis in 2016. In 2020 Kim Berg Hansen started handling guidelines maintenance, letting Philipp concentrate on the related [Trivadis db* CODECOP](https://cdn.trivadis.com/downloads/dbCODECOP-fs-en.pdf) tool.
+The first version of these guidelines was compiled by Roger Troller on March 17, 2009. Jörn Kulessa, Daniela Reiner, Richard Bushnell, Andreas Flubacher and Thomas Mauch helped Roger complete version 1.2 until August 21, 2009. This was the first GA version. The handy printed version in A5 format was distributed free of charge at the DOAG Annual Conference and on other occasions. Since then Roger updated the guidelines regularily. Philipp Salvisberg was involved in the review process for version 3.0 which was a major update. Philipp took the lead, after Roger left Trivadis in 2016. In 2020 Kim Berg Hansen started handling guidelines maintenance, letting Philipp concentrate on the related [Trivadis db* CODECOP](https://github.com/search?q=topic%3Acodecop+org%3ATrivadis+fork%3Atrue&type=repositories) tool suite.
 
 Since July, 7 2018 these guidelines are hosted on GitHub. Ready to be enhanced by the community and forked to fit specific needs.