Describe interoperability with neo4j gem

README.md

@@ -56,6 +56,22 @@ You can run any or all of the above graph databases. Pacer supports
 running them simultaneuosly and even supports having many of any given
 type open at once.
 
+### Interoperation with the neo4j gem
+
+Pacer can work together with other Ruby GraphDB libraries, too. The
+first functioning example is with theo neo4j gem. Hopefully more will
+follow soon as I find out about them or get requests to support them.
+
+To use Pacer together with the neo4j gem, get your Pacer graph instance
+as follows:
+
+    graph = Pacer.neo4j(Neo4j.db.graph)
+
+After that, you can continue to use the graph as normal with *both*
+gems. Any update that's committed with one gem will be visible
+immediately to the other because they are now both pointing to the same
+Java graphdb instance.
+
 ### A note on safely exiting
 
 Some databases need to be shutdown cleanly when the program exits. You