def add_unique_index(columns, index_name = nil)
      options = { unique: true }
      options.merge!(name: index_name) if index_name # rubocop:disable Performance/RedundantMerge

      migration.add_index(table_name, columns, options)
    end
def add_unique_index(columns, index_name = nil)
      options = { unique: true }
      options.merge!(name: index_name) if index_name # rubocop:disable Performance/RedundantMerge

      migration.add_index(table_name, columns, options)
    end
Adds a unique index on the given columns, with the provided name if passed

 @param columns [Array<String>, Array<Symbol>, String, Symbol]
 @param index_name [String]