create index concurrently on topic column in library_item table

packages/db/migrations/0177.do.public_item.sql

@@ -87,6 +87,4 @@ ALTER TABLE omnivore.library_item
     ADD COLUMN topic LTREE,
     ADD COLUMN score FLOAT;
 
-CREATE INDEX library_item_topic_idx ON omnivore.library_item USING GIST (topic);
-
 COMMIT;

packages/db/migrations/0183.do.library_item_topic_idx.sql

@@ -0,0 +1,5 @@
+-- Type: DO
+-- Name: library_item_topic_idx
+-- Description: Create index on topic column in library_item table
+
+CREATE INDEX CONCURRENTLY IF NOT EXISTS library_item_topic_idx ON omnivore.library_item USING GIST (topic);

packages/db/migrations/0183.undo.library_item_topic_idx.sql

@@ -0,0 +1,9 @@
+-- Type: UNDO
+-- Name: library_item_topic_idx
+-- Description: Create index on topic column in library_item table
+
+BEGIN;
+
+DROP INDEX IF EXISTS library_item_topic_idx;
+
+COMMIT;