Add trading agents directory for appuser

Create a directory for trading agents and set ownership to fix the PermissionError I faced. Hopefully will fix for other users as well.

Dockerfile

@@ -19,6 +19,8 @@ COPY --from=builder /opt/venv /opt/venv
 ENV PATH="/opt/venv/bin:$PATH"
 
 RUN useradd --create-home appuser
+RUN mkdir -p /home/appuser/.tradingagents
+RUN chown -R appuser:appuser /home/appuser/.tradingagents
 USER appuser
 WORKDIR /home/appuser/app