Wait for mysql to be up before executing

docker-entrypoint.sh

@@ -1,3 +1,15 @@
 #!/bin/sh
+
+set -e
+
+until nc -z -v -w30 $DATABASE_HOST 3306
+do
+  echo "Waiting for database connection..."
+  # wait for 5 seconds before check again
+  sleep 5
+done
+
+echo "Mysql is up - executing command"
+
 cd /usr/src/app/
 node index.js -h $DATABASE_HOST -p $DATABASE_PASSWORD -d $DATABASE_NAME -u $DATABASE_USER -n 80 -r 0.0.0.0