diff --git a/synapse/docker-compose.yml b/synapse/docker-compose.yml
index ebc9f98..532e298 100644
--- a/synapse/docker-compose.yml
+++ b/synapse/docker-compose.yml
@@ -5,6 +5,8 @@ services:
     working_dir: /config
     volumes:
       - ${MAS_CONFIG_DIR}:/config
+    environment:
+      MAS_CONFIG: ${MAS_CONFIG_DIR}/config.yaml
     ports:
       - "8090:8090"
     depends_on: