database.rules.json

{
  "rules": {
    "signups": {
      ".write": true,
      ".read": false
    },
    "users": {
      ".write": "auth !== null && auth.provider === 'github'",
      ".read": "auth !== null && auth.provider === 'github'",
      "$uid": {
        ".read": "auth != null && auth.uid == $uid",
        ".write": "auth != null && auth.uid == $uid"
      }
    },
    "v1": {
      "users": {
        ".write": "auth !== null && auth.provider === 'github'",
        ".read": "auth !== null && auth.provider === 'github'",
        "$uid": {
          ".read": "auth != null && auth.uid == $uid",
          ".write": "auth != null && auth.uid == $uid"
        }
      },
      "signups": {
        ".write": true,
        ".read": false
      }
    }
  }
}