Adjusted entrypoint.sh to actually build binary

backend/entrypoint.sh

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