firebase.json

{
  "database": {
    "rules": {
      "tasks": {
        "$uid": {
          ".read": "auth !== null && auth.uid === $uid",
          ".write": "auth !== null && auth.uid === $uid",
          ".indexOn": ["completed"]
        }
      }
    }
  },

  "hosting": {
    "public": "target",
    "headers": [
      {
        "source": "**/*",
        "headers": [
          {"key": "X-Content-Type-Options", "value": "nosniff"},
          {"key": "X-Frame-Options", "value": "DENY"},
          {"key": "X-UA-Compatible", "value": "ie=edge"},
          {"key": "X-XSS-Protection", "value": "1; mode=block"}
        ]
      },
      {
        "source": "**/*.@(css|html|js|map)",
        "headers": [
          {"key": "Cache-Control", "value": "max-age=7200"}
        ]
      }
    ],
    "rewrites": [
      {"source": "**", "destination": "/index.html"}
    ]
  }
}