Merge pull request #341 from DLR-AMR/feature-link_docu_in_readme

Update README.md

README.md

@@ -120,8 +120,21 @@ For a debugging mode with static linkage (makes using gdb and valgrind more comf
   and read the corresponding Wiki pages starting with [Step 0 - Helloworld](https://github.com/holke/t8code/wiki/Step-0---Hello-World).
 
   A sophisticated example of a complete numerical simulation is our finite volume solver of the advection equation in `example/advection`.
-
-  ### Publications
+
+
+### Documentation
+
+t8code uses [Doxygen](https://doxygen.nl/) to generate the code documentation. You can build the documentation with
+
+```
+make doxygen
+```
+
+and then find the generated files in the `/doxygen` subfolder.
+
+You can also find the documentation of our releases on the [t8code website](https://dlr-amr.github.io/t8code/pages/documentation.html).
+
+### Publications
 
   An (incomplete) list of publications related to t8code: