Add Dockerfile

.devcontainer/Dockerfile

@@ -0,0 +1,21 @@
+# See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.208.0/containers/dotnet/.devcontainer/base.Dockerfile
+
+# [Choice] .NET version: 6.0, 5.0, 3.1, 6.0-bullseye, 5.0-bullseye, 3.1-bullseye, 6.0-focal, 5.0-focal, 3.1-focal
+ARG VARIANT="7.0-bullseye-slim"
+FROM mcr.microsoft.com/vscode/devcontainers/dotnet:0-${VARIANT}
+
+# [Choice] Node.js version: none, lts/*, 16, 14, 12, 10
+ARG NODE_VERSION="none"
+RUN if [ "${NODE_VERSION}" != "none" ]; then su vscode -c "umask 0002 && . /usr/local/share/nvm/nvm.sh && nvm install ${NODE_VERSION} 2>&1"; fi
+
+# [Optional] Uncomment this section to install additional OS packages.
+# RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
+#     && apt-get -y install --no-install-recommends <your-package-list-here>
+
+RUN apt-get update && apt-get install -y --no-install-recommends apt-transport-https dirmngr gnupg ca-certificates \
+    && apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF \
+    && echo "deb https://download.mono-project.com/repo/debian stable-buster main" | tee /etc/apt/sources.list.d/mono-official-stable.list \
+    && apt-get update
+
+# [Optional] Uncomment this line to install global node packages.
+# RUN su vscode -c "source /usr/local/share/nvm/nvm.sh && npm install -g <your-package-here>" 2>&1