fix: add default CMD to list files in working directory

Dockerfile

@@ -56,6 +56,7 @@ RUN sudo apt update -y && sudo apt upgrade -y && \
 # Install Python dependencies from requirements.txt
 RUN pip install --no-cache-dir -r requirements.txt
 WORKDIR $HOME/app
+CMD ["ls -a"]
 
 # Expose the port for the app
 EXPOSE 7860