class ActiveRecord::ConnectionAdapters::SQLite3Adapter

def copy_table_indexes(from, to, rename = {})
  indexes(from).each do |index|
    name = index.name
    if to == "a#{from}"
      name = "t#{name}"
    elsif from == "a#{to}"
      name = name[1..-1]
    end
    columns = index.columns
    if columns.is_a?(Array)
      to_column_names = columns(to).map(&:name)
      columns = columns.map { |c| rename[c] || c }.select do |column|
        to_column_names.include?(column)
      end
    end
    unless columns.empty?
      # index name can't be the same
      options = { name: name.gsub(/(^|_)(#{from})_/, "\\1#{to}_"), internal: true }
      options[:unique] = true if index.unique
      options[:where] = index.where if index.where
      options[:order] = index.orders if index.orders
      add_index(to, columns, **options)
    end
  end
end