Update Dockerfile

Dockerfile

@@ -19,7 +19,8 @@ RUN apt-get update && apt-get install -y ffmpeg wget tar && rm -rf /var/lib/apt/
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
-RUN python -m nltk.downloader cmudict
+RUN mkdir -p /app/cache/nltk_data && \
+    python -m nltk.downloader cmudict -d /app/cache/nltk_data
 
 # Copy all code
 COPY . .