Push builds to cachix

.github/workflows/build_test.yml

@@ -67,3 +67,23 @@ jobs:
               run: cargo test
               env:
                   SQLX_OFFLINE: "true"
+    build:
+        name: Build
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v2
+            - uses: cachix/install-nix-action@v20
+              with:
+                github_access_token: ${{ secrets.GITHUB_TOKEN }}
+            - uses: actions-rs/toolchain@v1
+              id: cargo
+              with:
+                  toolchain: stable
+                  components: clippy
+            - uses: cachix/cachix-action@v12
+              with:
+                name: natsukagami
+                # If you chose API tokens for write access OR if you have a private cache
+                authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+            - name: Run nix build
+              run: nix build

flake.nix

@@ -6,6 +6,10 @@
     naersk.inputs.nixpkgs.follows = "nixpkgs";
     flake-utils.url = "github:numtide/flake-utils";
   };
+  nixConfig = {
+    extra-substituters = [ "https://natsukagami.cachix.org" ];
+    trusted-public-keys = [ "natsukagami.cachix.org-1:3U6GV8i8gWEaXRUuXd2S4ASfYgdl2QFPWg4BKPbmYiQ=" ];
+  };
   outputs = { self, nixpkgs, naersk, flake-utils, ... }: flake-utils.lib.eachDefaultSystem (system:
     let
       pkgs = import nixpkgs { inherit system; };
@@ -27,6 +31,8 @@
         nativeBuildInputs = nixpkgs.lib.optionals pkgs.stdenv.isLinux (with pkgs; [
           pkg-config
         ]);
+
+        SQLX_OFFLINE = "true";
       };
 
       defaultPackage = packages.youmubot;