fix(space): point Docker to backend FastAPI app

Dockerfile

@@ -1,9 +1,11 @@
 FROM python:3.10-slim
-RUN useradd -m -u 1000 user
-USER user
-ENV PATH="/home/user/.local/bin:$PATH"
+
 WORKDIR /app
-COPY --chown=user ./requirements.txt /app/requirements.txt
-RUN pip install --no-cache-dir --upgrade -r /app/requirements.txt
-COPY --chown=user . /app
-CMD ["uvicorn", "app:app", "--host", "0.0.0.0", "--port", "7860"]
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir --upgrade -r requirements.txt
+
+COPY . .
+
+EXPOSE 7860
+CMD ["uvicorn", "backend.main:app", "--host", "0.0.0.0", "--port", "7860"]