Add index for description in ci_runners table

Changelog: added

db/migrate/20210602122233_add_runners_description_index.rb

+# frozen_string_literal: true
+
+class AddRunnersDescriptionIndex < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  INDEX_NAME = 'index_ci_runners_on_description_trigram'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :ci_runners, :description, name: INDEX_NAME, using: :gin, opclass: { description: :gin_trgm_ops }
+  end
+
+  def down
+    remove_concurrent_index_by_name :ci_runners, INDEX_NAME
+  end
+end

db/schema_migrations/20210602122233

+96c70de2567fc3e816c720ed6e4cef2446c0f0ee288d0959cd1298523913077f
\ No newline at end of file

db/structure.sql

@@ -22921,6 +22921,8 @@ CREATE INDEX index_ci_runner_projects_on_runner_id ON ci_runner_projects USING b
 
 CREATE INDEX index_ci_runners_on_contacted_at ON ci_runners USING btree (contacted_at);
 
+CREATE INDEX index_ci_runners_on_description_trigram ON ci_runners USING gin (description gin_trgm_ops);
+
 CREATE INDEX index_ci_runners_on_locked ON ci_runners USING btree (locked);
 
 CREATE INDEX index_ci_runners_on_runner_type ON ci_runners USING btree (runner_type);