docs: Update documentation and Doxygen documentation generation
diff --git a/utils/tracers/ipv4-app-tracer.h b/utils/tracers/ipv4-app-tracer.h
index 0322d96..d574117 100644
--- a/utils/tracers/ipv4-app-tracer.h
+++ b/utils/tracers/ipv4-app-tracer.h
@@ -29,6 +29,10 @@
 
 class Ipv4Header;
 
+/**
+ * @ingroup ndn-tracers
+ * @brief Base class for IPv4/TCP based applications
+ */
 class Ipv4AppTracer : public SimpleRefCount<Ipv4AppTracer>
 {
 public: