Trello custom progress bar

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Trello custom progress bar",
  "short_name": "Trello custom progress bar",
  "description": "Customize you Trello progress bar",
  "version": "1.2",
  "permissions": [
    "tabs",
    "storage",
    "webNavigation"
  ],
  "browser_action": {
    "default_title": "blahblah",
    "default_icon": {
      "32": "32.png"
    }
  },
  "background": {
    "matches": [
      "*://trello.com/c/*"
    ],
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "icons": {
    "32": "32.png",
    "48": "48.png",
    "128": "128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://trello.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "*.png"
  ],
  "options_page": "options.html"
}