add server sent events

src/realtime.ts

@@ -0,0 +1,11 @@
+import { EventEmitter } from "stream";
+import { Claim } from "./utils/claims";
+
+export type ChangeEvent = {
+  type: "insert" | "update" | "delete";
+  collection: "permits" | "orgs";
+  document?: Object;
+  requiredClaims: Claim[];
+};
+
+export const dbEvents = new EventEmitter();