Add unsend campaign feature (#45)

* Add unsend email editor

Add email editor

Add more email editor

Add renderer partial

Add more marketing email features

* Add more campaign feature

* Add variables

* Getting there

* campaign is there mfs

* Add migration

apps/web/src/hooks/useInterval.ts

@@ -0,0 +1,25 @@
+import { useEffect, useRef } from "react";
+
+export function useInterval(callback: () => void, delay: number | null) {
+  const savedCallback = useRef<() => void>();
+
+  // Remember the latest callback.
+  useEffect(() => {
+    savedCallback.current = callback;
+  }, [callback]);
+
+  // Set up the interval.
+  useEffect(() => {
+    function tick() {
+      if (savedCallback.current) {
+        savedCallback.current();
+      }
+    }
+    if (delay !== null) {
+      const id = setInterval(tick, delay);
+      return () => clearInterval(id);
+    }
+  }, [delay]);
+}
+
+export default useInterval;