chore: Typescript database models (#2886)

closes #2798

server/policies/group.ts

@@ -1,8 +1,6 @@
 import { Group, User, Team } from "@server/models";
 import { AdminRequiredError } from "../errors";
-import policy from "./policy";
-
-const { allow } = policy;
+import { allow } from "./cancan";
 
 allow(User, "createGroup", Team, (actor, team) => {
   if (!team || actor.isViewer || actor.teamId !== team.id) return false;