Add declarative script injection

Author: sudonatalie

js/background.js

@@ -1,5 +1,8 @@
 const boardUrl = 'trello.com/b/';
 
+// Declarative content script injection doesn't work on push state (i.e. when
+// navigating from trello.com/username/boards to a specific board page), so we
+// re-inject content scripts programmatically onHistoryStateUpdated.
 chrome.webNavigation.onHistoryStateUpdated.addListener(function(details) {
   // Match Trello board pages only
   const match = details.url.includes(boardUrl);

manifest.json

@@ -13,6 +13,11 @@
       "js/background.js"
     ]
   },
+  "content_scripts": [{
+    "matches": ["*://trello.com/b/*"],
+    "css": ["css/layout.css"],
+    "js": ["js/init.js"]
+  }],
   "permissions": [
     "*://trello.com/b/*",
     "declarativeContent",