add database schema

dbschema/default.gel

@@ -1,3 +1,40 @@
 module default {
+  scalar type access_status extending enum<ok, denied, expired, error>;
 
+  type files {
+    required file_id: str;
+    required file_name: str;
+
+    required note: str {
+      readonly := true;
+    }
+    required content_type: str {
+      readonly := true;
+    }
+    required expires_at: datetime {
+      readonly := true;
+    }
+    required uploaded_at: datetime {
+      readonly := true;
+    }
+
+    multi accesses -> file_access;
+
+    index on ((.file_id, .file_name, .expires_at));
+  }
+
+  type file_access {
+    required ip: str;
+    required status: access_status {
+      default := access_status.ok;
+    }
+
+    user_agent: str {
+      readonly := true;
+    };
+    required at: datetime {
+      readonly := true;
+      default := datetime_of_statement();
+    }
+  }
 }