database.rules.json

{
  "rules": {
    ".read": true,

    "examples": {
      ".write": false
    },

    "projects": {
      ".indexOn": "owner",

      "$uid": {
        ".write": "!data.parent().child('owner').exists() || (auth != null && data.child('owner').hasChild('auth.uid'))",
        "name": {
          ".validate": "newData.isString() && newData.val().length <= 30"
        },

        "scripts": {
          "$sid": {
            "name": {
              ".validate": "newData.isString() && newData.val().length <= 20"
            }
          }
        },

        "resources": {
          "$rid": {
            "name": {
              ".validate": "newData.isString() && newData.val().length <= 20"
            }
          }
        }
      }
    }
  }
}