Add docker files to run nix dev environment on Windows

nix/Dockerfile

@@ -0,0 +1,22 @@
+# This Dockerfile is only used as a development environment for
+# non-nix systems, i.e. Windows.
+
+FROM nixos/nix:latest
+
+RUN apk --no-cache add \
+    wget
+
+RUN nix-env -iA cachix -f https://cachix.org/api/v1/install \
+ && cachix use postgrest
+
+# We need an unprivileged user here, to make PG run at all.
+RUN adduser --disabled-password --ingroup root nix \
+ && chown -R nix:root /nix
+USER nix:root
+ENV USER=nix
+
+VOLUME /nix
+VOLUME /postgrest
+WORKDIR /postgrest
+
+CMD nix-shell

nix/README.md

@@ -12,6 +12,11 @@ their dependencies will be stored. It will also link the Nix executables like
 other PostgREST dependencies from here on out. To clean up older build
 artifacts from the `/nix/store`, you can run `nix-collect-garbage`.
 
+If you are on a system that does not support nix, for example Windows, you can
+run the nix development environment in a docker container. Inside the `nix/`
+directory run `docker-compose run --rm nix` to start the docker container. This
+will set up the binary cache and launch `nix-shell` automatically.
+
 ## Building PostgREST
 
 To build PostgREST from your local checkout of the repository, run:

nix/docker-compose.yml

@@ -0,0 +1,12 @@
+version: '3'
+
+services:
+  nix:
+    container_name: postgrest-nix
+    build: .
+    volumes:
+      - ../:/postgrest
+      - nix:/nix
+
+volumes:
+  nix: