added warning in Docker env for missing gh token

Author: pirafrank

entrypoint.sh

@@ -1,6 +1,12 @@
 #!/usr/bin/env bash
 
 set -e
+
+if [ -z "$GITHUB_TOKEN" ]; then
+  echo "GITHUB_TOKEN is not set. Exiting."
+  exit 1
+fi
+
 argv=(node /app/github.js "$@")
 cmd=$(printf '%q ' "${argv[@]}")
 eval $cmd