Fixing id1_type index instruction. Without adding id2, range scans

not including id2 column do not use covering index, if storage
engines do not include primary key values within secondary index
(i.e. MyISAM).

README.md

@@ -278,7 +278,7 @@ After loading you should revert the changes:
     set global innodb_flush_log_at_trx_commit = 1;
     set global sync_binlog = 1;
     alter table linktable add key `id1_type`
-      (`id1`,`link_type`,`visibility`,`time`,`version`,`data`);
+      (`id1`,`link_type`,`visibility`,`time`,`id2`,`version`,`data`);
 
 Request Phase
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