in lib/active_record/connection_adapters/abstract/schema_statements.rb there is a missing quote_table_name in line 286 (def remove_index):
execute "DROP INDEX #{quote_column_name(index_name(table_name, options))} ON #{table_name}"
so my "keys" table can get an index with "add_index" but can't remove it (without tweaking)
replacing it to
execute "DROP INDEX #{quote_column_name(index_name(table_name, options))} ON #{quote_table_name(table_name)}"
would help (and would be logical).
Best regards Savar