add in some reader mode fun (#303)

tabs-tabs-tabs/manifest.json

@@ -1,4 +1,9 @@
 {
+  "applications": {
+    "gecko": {
+      "strict_min_version": "58.0a1"
+    }
+  },
   "background": {
       "scripts": ["background.js"]
   },

tabs-tabs-tabs/tabs.html

@@ -28,6 +28,10 @@
 
     <div class="panel-section-separator"></div>
 
+    <a href="#" id="tabs-create-reader">Create a tab in reader mode</a><br>
+
+    <div class="panel-section-separator"></div>
+
     <a href="#" id="tabs-add-zoom">Zoom in</a><br>
     <a href="#" id="tabs-default-zoom">Reset zoom</a><br>
     <a href="#" id="tabs-decrease-zoom">Zoom out</a><br>

tabs-tabs-tabs/tabs.js

@@ -102,6 +102,10 @@ document.addEventListener("click", (e) => {
     browser.tabs.create({url: "https://developer.mozilla.org/en-US/Add-ons/WebExtensions"});
   }
 
+  else if (e.target.id === "tabs-create-reader") {
+    browser.tabs.create({url: "https://developer.mozilla.org/en-US/Add-ons/WebExtensions", openInReaderMode: true});
+  }
+
   else if (e.target.id === "tabs-alertinfo") {
     callOnActiveTab((tab) => {
       let props = "";