Finally switch to flakes.

nixos/server/mastodon.nix

@@ -0,0 +1,19 @@
+{pkgs, ...}: {
+  services.mastodon = let 
+    secrets = import ../common/secrets.nix;
+  in {
+    enable = true;
+    localDomain = "social.${secrets.jimDomain}";
+    streamingProcesses = 4;
+    configureNginx = true;
+    smtp = {
+      createLocally = false;
+      host = "mx.${secrets.jimDomain}";
+      port = 587;
+      authenticate = true;
+      fromAddress = "Jimbo's Mastodon <noreply@${secrets.jimDomain}>";
+      user = "noreply@${secrets.jimDomain}";
+      passwordFile = pkgs.writeText "smtp_pass.txt" secrets.noreplyPassword;
+    };
+  };
+}