Add warning

README.md

@@ -16,6 +16,10 @@ Build REST APIs with Neo4j and Flask, as quickly as possible!
 
 gREST (Graph-based REST API Framework) is a RESTful API development framework on top of Python, Flask, Neo4j and Neomodel. Its primary purpose is to ease development of RESTful APIs with little effort and minimum amount of code.
 
+## ⚠️ WARNING ⚠️
+
+This package is not maintained regularly and there might be many issues, which is due to the constraints on my time and interest to contribute to its development. The original idea was to devise a simple way to store and traverse graph-based data and to create REST APIs on top of Flask and Neo4j. Today, there are many standard industry-proven technologies such as GraphQL that can do the job much better than gREST. Still, I'd be happy to help you if you have issues.
+
 ## Python Version Compatibility
 
 If you want to use gREST with Python 2.7, you will need to stick with the good old [1.4.0](https://pypi.org/project/pygrest/1.4.0/) version. For Python 3.x onwards, use the latest version starting with 2.x.x or the `master` branch.