Add default entrypoint.sh

backend/entrypoint.sh

@@ -1,8 +1,4 @@
 #!/bin/sh
 set -e
 
-echo "Container's IP address: `awk 'END{print $1}' /etc/hosts`"
-
-cd /backend
-
-make
+echo "Container's IP address: `awk 'END{print $1}' /etc/hosts`"