Images built on the top of nasqueron/nginx-php-fpm to offer a specific application seems currently to work like this:

RUN cd /opt && git clone <application repository> && ...

We can so avoid this step only for one package if we include Git directly in the image:

RUN apt-get update && apt-get install -y \
            git \
            --no-install-recommends && rm -r /var/lib/apt/lists/*