Merge pull request #64 from CosmWasm/aw/nix-flake

Add Nix flake

flake.nix

@@ -0,0 +1,44 @@
+{
+  description = "Dependencies for development";
+
+  inputs = {
+    flake-utils.url = "github:numtide/flake-utils";
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs, flake-utils } @ imports: (
+    flake-utils.lib.eachDefaultSystem (
+      system: (
+        let
+          overlays = [
+          ];
+          pkgs = import nixpkgs { inherit overlays system; };
+          baseDependencies = with pkgs; [
+            python3
+          ];
+        in
+        {
+          formatter = pkgs.nixpkgs-fmt;
+          devShells = rec {
+            default = docs;
+            docs = pkgs.mkShell {
+              buildInputs = with pkgs; [
+                nodejs
+              ]
+              ++ baseDependencies;
+            };
+            doc-tests = pkgs.mkShell {
+              buildInputs = with pkgs; [
+                cargo
+                rustc
+                rustfmt
+              ]
+              ++ lib.optionals stdenv.isDarwin [libiconv]
+              ++ baseDependencies;
+            };
+          };
+        }
+      )
+    )
+  );
+}