Added doxygen documentation to GitLab pages as suggested in https://github.com/openjournals/joss-reviews/issues/1592#issuecomment-515643495

.gitignore

@@ -24,3 +24,5 @@ status_code_test
 
 # Visual Studio 2015/2017 cache/options directory
 .vs
+
+doxygen/documentation

.gitlab-ci.yml

@@ -34,3 +34,16 @@ static-analysis:
   image: "registry.gitlab.com/eidheim/docker-images:arch"
   script:
     - scan-build cmake .. && scan-build --status-bugs make
+
+pages:
+  image: alpine
+  script:
+    - apk update && apk add doxygen
+    - cd .. && doxygen doxygen/Doxyfile
+    - mv doxygen/documentation/html/ public/
+  artifacts:
+    paths:
+    - public
+  only:
+    - master
+

README.md

@@ -20,9 +20,11 @@ See https://gitlab.com/eidheim/Simple-WebSocket-Server for an easy way to make W
 
 ### Usage
 
-See [http_examples.cpp](http_examples.cpp) or [https_examples.cpp](https_examples.cpp) for example usage. 
+See [http_examples.cpp](https://gitlab.com/eidheim/Simple-Web-Server/blob/master/http_examples.cpp) or
+[https_examples.cpp](https://gitlab.com/eidheim/Simple-Web-Server/blob/master/https_examples.cpp) for example usage.
+Particularly, the JSON-POST (using Boost.PropertyTree) and the GET /match/[number] examples might be relevant.
 
-See particularly the JSON-POST (using Boost.PropertyTree) and the GET /match/[number] examples, which are most relevant.
+[Documentation](https://eidheim.gitlab.io/Simple-Web-Server/annotated.html) is also available, generated from the master branch.
 
 ### Dependencies