manifest.json

{
"name":"Measure Material",
"short_name":"Material",
"icons": [{
    "src": "images/hello-icon-128.png",
      "sizes": "128x128",
      "type": "image/png"
    }, {
      "src": "images/hello-icon-144.png",
      "sizes": "144x144",
      "type": "image/png"
    }, {
      "src": "images/hello-icon-152.png",
      "sizes": "152x152",
      "type": "image/png"
    }, {
      "src": "images/hello-icon-192.png",
      "sizes": "192x192",
      "type": "image/png"
    }, {
      "src": "images/hello-icon-256.png",
      "sizes": "256x256",
      "type": "image/png"
    }, {
      "src": "images/hello-icon-512.png",
      "sizes": "512x512",
      "type": "image/png"
    }],
    "lang":"en-US",
    "start_url":"./index.html",
    "display":"fullscreen",
    "background_color":"#4a148c",
    "theme_color":"#6A1B9A"
}