Add firefox extension

extensions/firefox/background.js

@@ -0,0 +1,18 @@
+function updateRedirects() {
+  var URL =
+    "https://raw.githubusercontent.com/davegallant/rfd-redirect-stripper/main/redirects.json";
+
+  fetch(URL)
+    .then((res) => res.json())
+    .then((res) => {
+      browser.storage.local.set({
+        "rfd-redirects": res,
+      });
+    });
+}
+
+chrome.runtime.onInstalled.addListener(() => {
+  updateRedirects();
+});
+
+setInterval(updateRedirects, 1 * 60 * 60 * 1000);