reduce amount of rebuilding for fly deployments

fly.dockerfile

@@ -4,8 +4,19 @@ LABEL maintainer="Zauberzeug GmbH <nicegui@zauberzeug.com>"
 
 RUN pip install itsdangerous prometheus_client isort docutils pandas plotly matplotlib requests
 
+RUN apt update && apt install curl -y
+
+RUN curl -sSL https://install.python-poetry.org | python3 - && \
+    cd /usr/local/bin && \
+    ln -s ~/.local/bin/poetry && \
+    poetry config virtualenvs.create false
+
 WORKDIR /app
 
+COPY pyproject.toml poetry.lock*  ./
+
+RUN poetry install --no-root --extras "plotly matplotlib"
+
 ADD . .
 
 # ensure unique version to not serve cached and hence potentially wrong static files