feat: initial add of flake for builds

.gitignore

@@ -1,3 +1,4 @@
 /target
 /_test_area
 /site
+/result

flake.nix

@@ -0,0 +1,70 @@
+{
+  description = "an opinionated documentation site generator";
+
+  # inputs needed for rust along with some nice tooling for development environment
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs";
+    utils.url = "github:numtide/flake-utils";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+    naersk.url = "github:nix-community/naersk";
+  };
+
+  outputs = { self, nixpkgs, utils, rust-overlay, naersk, ... }:
+    let
+      name = "doctave";
+    in
+    utils.lib.eachDefaultSystem (system:
+      let
+        # nix packages with rust overlay defaulats instead
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [
+            rust-overlay.overlay
+            (self: super: {
+              rustc = self.rust-bin.stable.latest.default;
+              cargo = self.rust-bin.stable.latest.default;
+            })
+          ];
+        };
+
+        # override version cargo and rustc version of naersk with overlay
+        naersk-lib = naersk.lib.${system}.override {
+          cargo = pkgs.cargo;
+          rustc = pkgs.rustc;
+        };
+
+      in
+      rec {
+        # main package to base all builds from
+        packages.${name} = naersk-lib.buildPackage {
+          pname = name;
+          # root of rust source holding cargo.lock
+          root = ./.;
+        };
+        defaultPackage = packages.${name};
+        # build out a container image if want to run as a container
+        packages.container = pkgs.dockerTools.buildImage {
+          inherit name;
+          tag = packages.${name}.version;
+          created = "now";
+          contents = packages.${name};
+          config.Cmd = [ "${packages.${name}}/bin/doctave" ];
+        };
+        # useful default app to run from nix directly
+        apps.${name} = utils.lib.mkApp {
+          inherit name;
+          drv = packages.${name};
+        };
+        defaultApp = apps.${name};
+
+        # dev shell default
+        devShell = pkgs.mkShell {
+          shellHook = ''
+            export RUST_SRC_PATH=${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}
+          '';
+
+          nativeBuildInputs = [ pkgs.cargo ];
+        };
+      }
+    );
+}