Temporary workaround for scoped_search issue

https://github.com/wvanbergen/scoped_search/issues/52

Fixes

```
ActiveRecord::StatementInvalid: PGError: ERROR:  syntax error at or near "FIRST"

LINE 1: ...fig_templates".id, "config_templates"."name"NULLS FIRST  AS ...

 SELECT  DISTINCT "config_templates".id, "config_templates"."name"NULLS FIRST  A
S alias_0 FROM "config_templates" LEFT OUTER JOIN "taxable_taxonomies" ON "taxab
le_taxonomies"."taxable_id" = "config_templates"."id" AND "taxable_taxonomies"."
taxable_type..."
```