add unique index to lists table
add unique index to lists table

steemit/steemit.com,steemit/steemit.com,enisey14/platform,GolosChain/tolstoy,TimCliff/steemit.com,TimCliff/steemit.com,enisey14/platform,GolosChain/tolstoy,steemit/steemit.com,GolosChain/tolstoy,TimCliff/steemit.com