[repacker] Add comment to graph class.
diff --git a/src/graph/graph.hh b/src/graph/graph.hh
index ed37352..52ca9dd 100644
--- a/src/graph/graph.hh
+++ b/src/graph/graph.hh
@@ -29,6 +29,10 @@
 
 namespace graph {
 
+/**
+ * Represents a serialized table in the form of a graph.
+ * Provides methods for modifying and reordering the graph.
+ */
 struct graph_t
 {
   struct vertex_t