Add example dockerfile

Dockerfile

@@ -0,0 +1,31 @@
+# Use an official Debian image as a parent image
+FROM debian:buster
+
+# Set environment variables
+ENV SBCL_HOME=/opt/sbcl
+ENV QUICKLISP_HOME=/home/lisp/quicklisp
+
+# Install system dependencies
+RUN apt-get update && apt-get install -y \
+    sbcl \
+    curl \
+    --no-install-recommends && \
+    rm -rf /var/lib/apt/lists/*
+
+# Add a non-root user
+RUN useradd -ms /bin/bash lisp
+
+# Switch to the new user
+USER lisp
+WORKDIR /home/lisp
+
+# Download and install Quicklisp
+RUN curl -O https://beta.quicklisp.org/quicklisp.lisp && \
+    sbcl --noinform \
+         --non-interactive \
+         --load quicklisp.lisp \
+         --eval '(quicklisp-quickstart:install :path "$QUICKLISP_HOME")' \
+         --eval '(ql-util:without-prompting (ql:add-to-init-file))'
+
+# Set the default command to start SBCL configured with Quicklisp
+CMD ["sbcl"]