message: added clickhouse as supported db
  I believe clickhouse is supported now since was merged
diff: @@ -92,6 +92,7 @@ Superset can be used to visualize data out of most databases:
  * MonetDB
  * Snowflake
  * Redshift
  +* Clickhouse
  * **more!** look for the availability of a SQLAlchemy dialect for your database
  to find out whether it will work with Superset
  