Provide a minio server for development

- The server can be started with `nix run .#start-services start`
- Inside the `nix develop` environment, the AWS sdk will be properly
  configured to point at our local minio instance (and with valid
  credentials)

project.ncl

@@ -1,6 +1,8 @@
 let inputs = import "./nickel.lock.ncl" in
 let organist = inputs.organist in
 
+let minio_port = 9031 in
+
 {
   shells = organist.shells.Python310,
 
@@ -9,6 +11,20 @@ let organist = inputs.organist in
   },
 
   shells.dev = {
+    env = {
+      AWS_ENDPOINT_URL = "http://localhost:%{std.to_string minio_port}",
+      AWS_ACCESS_KEY_ID = "minioadmin",
+      AWS_SECRET_ACCESS_KEY = "minioadmin",
+    },
+  },
+
+  services = {
+    minio = nix-s%"
+%{organist.import_nix "nixpkgs#minio"}/bin/minio server --address :%{std.to_string minio_port} ./.minio-data
+    "%,
   },
 }
-  | organist.OrganistExpression
+  | (
+    organist.OrganistExpression
+    & organist.services.Schema
+  )