code: function SchemaBuilder(client) {
    this.client = client;
    this._sequence = [];
  
    if (client.config) {
      this._debug = client.config.debug;
      saveAsyncStack(this, 4);
    }
  }
docs: Constructor for the builder instance, typically called from `knex.builder`, accepting the current `knex` instance, and pulling out the `client` and `grammar` from the current knex instance.