class ActiveRecord::ConnectionAdapters::MySQL::SchemaCreation

def visit_IndexDefinition(o, create = false)
  index_type = o.type&.to_s&.upcase || o.unique && "UNIQUE"
  sql = create ? ["CREATE"] : []
  sql << index_type if index_type
  sql << "INDEX"
  sql << quote_column_name(o.name)
  sql << "USING #{o.using}" if o.using
  sql << "ON #{quote_table_name(o.table)}" if create
  sql << "(#{quoted_columns(o)})"
  add_sql_comment!(sql.join(" "), o.comment)
end