Got it working with nix flake

config.nix

@@ -1,5 +1,4 @@
 {
-  runDir = "/tmp/mediocre-blog/run";
   dataDir = "/tmp/mediocre-blog/data";
   publicURL = "http://localhost:4000";
 

flake.lock

@@ -0,0 +1,42 @@
+{
+  "nodes": {
+    "pkgsSrc": {
+      "locked": {
+        "lastModified": 1659914493,
+        "narHash": "sha256-lkA5X3VNMKirvA+SUzvEhfA7XquWLci+CGi505YFAIs=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "022caabb5f2265ad4006c1fa5b1ebe69fb0c3faf",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixos-21.05",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "pkgsSrc": "pkgsSrc",
+        "utils": "utils"
+      }
+    },
+    "utils": {
+      "locked": {
+        "lastModified": 1667395993,
+        "narHash": "sha256-nuEHfE/LcWyuSWnS8t12N1wc105Qtau+/OdUAjtQ0rA=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "5aed5285a952e0b949eb3ba02c12fa4fcfef535f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,63 @@
+{
+  inputs.pkgsSrc.url = "nixpkgs/nixos-21.05";
+  inputs.utils.url = "github:numtide/flake-utils";
+
+  outputs = {
+
+    self, pkgsSrc, utils
+
+  }: utils.lib.eachSystem utils.lib.allSystems (system: let
+
+    pkgs = import pkgsSrc { inherit system; };
+
+  in {
+
+    defaultPackage = pkgs.buildGoModule {
+      pname = "mediocre-blog";
+      version = "dev";
+      src = ./src;
+
+      vendorSha256 = "sha256:1vazrrg8rs9n8x40c9r53h9qnyxw59xkp0aq7jl15fliigk6q0cr";
+
+      subPackages = [ "cmd/mediocre-blog" ];
+
+      # disable tests
+      checkPhase = '''';
+    };
+
+    devShell = pkgs.mkShell {
+      buildInputs = [ pkgs.go pkgs.sqlite ];
+      shellHook = ''
+
+        export MEDIOCRE_BLOG_DATA_DIR="/tmp/mediocre-blog/data"
+
+        # mailing list
+        export MEDIOCRE_BLOG_ML_SMTP_ADDR=""
+        export MEDIOCRE_BLOG_ML_SMTP_AUTH=""
+        export MEDIOCRE_BLOG_ML_PUBLIC_URL="http://localhost:4000"
+
+        # pow
+        export MEDIOCRE_BLOG_POW_SECRET="ssshhh"
+
+        # http
+        export MEDIOCRE_BLOG_HTTP_PUBLIC_URL="$MEDIOCRE_BLOG_ML_PUBLIC_URL"
+        export MEDIOCRE_BLOG_HTTP_LISTEN_PROTO="tcp"
+        export MEDIOCRE_BLOG_HTTP_LISTEN_ADDR=":4000"
+
+        # http auth
+        # (password is "bar". This should definitely be changed for prod.)
+        export MEDIOCRE_BLOG_HTTP_AUTH_USERS='{"foo":"$2a$13$0JdWlUfHc.3XimEMpEu1cuu6RodhUvzD9l7iiAqa4YkM3mcFV5Pxi"}'
+        export MEDIOCRE_BLOG_HTTP_AUTH_RATELIMIT="1s"
+
+        cd src
+
+        echo 'Loading test data...'
+        (cd cmd/load-test-data && go run main.go)
+
+        echo -e "\n\nTest data has been loaded into $MEDIOCRE_BLOG_DATA_DIR\n"
+        echo -e "You can do 'go run ./cmd/mediocre-blog/main.go' to start a dev instance on http://localhost:4000\n\n"
+      '';
+    };
+
+  });
+}