feat: add healthcheck initialized check (#12)

Add a new check in the healthcheck to be sure that the sybase server is
ready

Author: cboudereau

healthcheck.sh

@@ -1,2 +1,4 @@
 #!/bin/sh
-netstat -ltn | grep 5000 || exit 1
+netstat -ltn | grep 5000 || exit 1
+
+if  [[ ! -f "/.initialized" ]]; then exit 1; fi