Update README.md to include QuestDB

QuestDB is the fastest growing open source time-series database, according to dbengines ranking. With thousands of users, 87 releases, 150 contributors, and over 15K github stars, it is a popular database for near-realtime or time-series data

Author: javier

README.md

@@ -88,6 +88,7 @@ Top must-join communities for ML:
   - [Apache Pinot](https://pinot.apache.org/)
   - [Apache Kylin](https://kylin.apache.org/)
   - [DuckDB](https://duckdb.org/)
+  - [QuestDB](https://questdb.io/)
 - LLM application library
   - [AdalFlow](https://github.com/SylphAI-Inc/AdalFlow)
   - [LangChain](https://github.com/langchain-ai/langchain)