link to the scalability blog post from workers.md

docs/workers.md

@@ -16,6 +16,9 @@ workers only work with PostgreSQL-based Synapse deployments. SQLite should only
 be used for demo purposes and any admin considering workers should already be
 running PostgreSQL.
 
+See also https://matrix.org/blog/2020/11/03/how-we-fixed-synapses-scalability
+for a higher level overview.
+
 ## Main process/worker communication
 
 The processes communicate with each other via a Synapse-specific protocol called