Improved: fixes a link in main README.adoc

Thanks to #868

Author: JacquesLeRoux

README.adoc

@@ -157,7 +157,7 @@ ________________________________________________________________________________
 
 [[Docker]]
 == Docker
-If you want to set and use Docker, link:DOCKER.html[here is the documentation]
+If you want to set and use Docker, link:https://nightlies.apache.org/ofbiz/trunk/readme/html5/DOCKER.html[here is the documentation]
 
 
 [[visit-ofbiz-through-your-browser]]