Ubuntu with Nix Installed (Dockerfile)

Dockerfile

FROM ubuntu:20.10
RUN apt-get update && \
  apt-get install -y sudo curl xz-utils && apt-get clean && \
  useradd builder -d /home/builder && \
  mkdir /home/builder && chown builder /home/builder && \
  echo "builder ALL=(root) NOPASSWD:ALL" > /etc/sudoers.d/user && \
  chmod 0440 /etc/sudoers.d/user && \
  (su builder --login -c 'curl -L https://nixos.org/nix/install | sh') && \
  apt-get remove -y curl xz-utils && apt-get autoremove -y && apt-get clean && \
  echo '. /home/builder/.nix-profile/etc/profile.d/nix.sh' >> /home/builder/.bashrc

USER builder
ENV USER builder
ENV PATH "/home/builder/.nix-profile/bin:$PATH"
ENV NIX_PROFILES /nix/var/nix/profiles/default /home/builder/.nix-profile
ENV NIX_PATH /home/builder/.nix-defexpr/channels
ENV NIX_SSL_CERT_FILE /etc/ssl/certs/ca-certificates.crt