#310 Mounting the existing code as an external volume

This was the only way of ensuring the code was fresh inside the docker
container. However, this comes with the challenge of actually compiling
code after the volume has been mounted, but before starting the daemon.

scenarios/1backend/docker-compose.yml

@@ -9,6 +9,8 @@ proxysql:
     - "6033:6033"
     # gdbserver
     - "2345:2345"
+  volumes:
+    - /tmp/proxysql-tests:/opt/proxysql
   privileged: true
 
 backend1hostgroup0: