add chmod

Dockerfile

@@ -7,6 +7,9 @@ WORKDIR /app
 # Copy the current directory contents into the container at /app
 COPY . /app
 
+# Create the flask_session directory and set the appropriate permissions
+RUN mkdir -p /app/flask_session && chmod 777 /app/flask_session
+
 # Install any needed packages specified in requirements.txt
 RUN pip install --no-cache-dir -r requirements.txt