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backend/Dockerfile

 FROM python:3.11-slim
 
-RUN apt-get update
-RUN apt-get install -y gcc libffi-dev
-
 ## make a local directory
 RUN mkdir /app
 
 # set "app" as the working directory from which CMD, RUN, ADD references
 WORKDIR /app
 
-# copy requirements.txt to /app
-ADD requirements.txt .
-
-# pip install the local requirements.txt
-RUN pip install -r requirements.txt
+# now copy all the files in this directory to /app
+COPY . .
 
-# now copy all the files in this directory to /code
-ADD . .
+# hadolint ignore=DL3008
+RUN apt-get update \
+  && apt-get install --no-install-recommends -y gcc libffi-dev \
+  && apt-get clean \
+  && rm -rf /var/lib/apt/lists/* \
+  && pip install --no-cache-dir -r requirements.txt
 
 # Listen to port 80 at runtime
 EXPOSE 5000