database.rules.json

{
  "rules": {
    "boards": {
      "$boardId": {
        ".validate": "newData.hasChildren(['boardId', 'user_id', 'max_votes', 'date_created'])",
        "boardId": {
          ".validate": "newData.isString()"
        },
        "user_id": {
          ".validate": "newData.val().length > 0 && newData.val() == auth.uid"
        },
        "max_votes": {
          ".validate": "newData.isNumber()"
        },
        "date_created": {
          ".validate": "newData.isString() || newData.isNumber()"
        },
        "text_editing_is_private": {
          ".validate": "newData.isBoolean()"
        },
        "columns": {
          ".validate": "newData.hasChildren()"
        },
        "boardContext": {
          ".validate": "newData.isString()"
        },
        "hide_vote": {
          ".validate": "newData.isBoolean()"
        },
        "$other": {
          ".validate": "false"
        },
        ".read": "data.child('user_id').val() == auth.uid",
        ".write": "newData.child('user_id').val() == auth.uid"
      }
    },
    "messages": {
      "$boardId": {
        "$messageId": {
          ".validate": "newData.hasChildren(['text', 'creating', 'user_id', 'type', 'date', 'date_created'])",
          "text": {
            ".validate": "newData.isString()"
          },
          "creating": {
            ".validate": "newData.isBoolean()"
          },
          "user_id": {
            ".validate": "newData.val().length > 0 && newData.val() == auth.uid"
          },
          "type": {
            ".validate": "newData.hasChildren()"
          },
          "date": {
            ".validate": "newData.isString() || newData.isNumber()"
          },
          "date_created": {
            ".validate": "newData.isString() || newData.isNumber()"
          },
          "votes": {
            ".validate": "newData.isNumber()"
          },
          "$other": {
            ".validate": "false"
          },
          ".read": "data.child('user_id').val() == auth.uid",
          ".write": "newData.child('user_id').val() == auth.uid"
        },
        ".read": "auth != null",
        ".write": "auth != null"
      }
    }
  }
}