add index merge to table up

db/postgresql/migrations/2021-11-28-093615_sent_sim_index_id/down.sql

@@ -1,3 +0,0 @@
--- This file should undo anything in `up.sql`
-
-DROP INDEX  IF EXISTS sent_sim_index_id ;

db/postgresql/migrations/2021-11-28-093615_sent_sim_index_id/up.sql

@@ -1,2 +0,0 @@
--- Your SQL goes here
-CREATE INDEX sent_sim_index_id ON sent_sim_indexs (sent_id);