Provide a Dockerfile that can be used to create a test environment

Provide a Dockerfile that can be used to create a test environment to
try out the Neovim config.

docker/Dockerfile

@@ -0,0 +1,35 @@
+FROM registry.fedoraproject.org/fedora:35
+
+WORKDIR /root/
+RUN dnf update -y
+
+RUN dnf install -y \
+    '@Development tools' \
+    fd-find \
+    gcc-c++ \
+    git \
+    htop \
+    libstdc++-devel \
+    ncdu \
+    npm \
+    nodejs \
+    python3 \
+    python3-devel \
+    python3-jedi \
+    python3-pip \
+    ripgrep \
+    rust \
+    wget \
+    && true
+
+# Uncomment this if prefer to use nightly builds
+# RUN dnf install -y 'dnf-command(copr)' \
+#     && dnf copr -y enable agriffis/neovim-nightly \
+#     && dnf install -y neovim python3-neovim
+
+RUN dnf install -y neovim python3-neovim
+# NOTE: As of 2021-12-18 neovim 0.6.0 is only available in the updates-testing repo
+RUN dnf --enablerepo=updates-testing update -y neovim
+
+RUN git clone https://github.com/LunarVim/Neovim-from-scratch.git ~/.config/nvim
+RUN pip install black flake8 isort mypy

docker/README.md

@@ -0,0 +1,12 @@
+Simple `Dockerfile` to create a Docker container based on Fedora 35, with a nightly build of Neovim.
+
+To build it use either `docker` or `podman`:
+
+```
+$ docker build -t neovim-playground .
+$ docker run -it neovim-playground bash
+```
+
+As described in https://www.youtube.com/watch?v=ctH-a-1eUME, you will need to
+run `nvim` twice to get Neovim setup and running. After than you can then try
+out the features mentioned in the video.