contextual gadget not deployed on marketplace

Question

i publish the Gadget on marketplace but only Domain user can install it... when i click on the "install" .. marketplace ask me for Domain id and password ..every user can not be install this Gadget... is there a way to my gadget can install every gmail user .

this is my manifeast.json

{
   "manifest_version": 2,
   "name": "unsendMe",
   "version": "0.0.0.2",

    "description": "Grab the contact of the mail sender and save .",

    "icons": {
    "128": "ICON_PLACE3 (2) (Custom) (2).png",
    "16": "ICON_PLACE3 (2) (Custom).png"
  },
     "container": ["DOMAIN_INSTALLABLE"],
     "api_console_project_id": "xxxxxxxxxxxx[app id]"
}