SearchIndexer is only automatically disabled in `before_all` and `before` blocks which means at the start
of test runs. Enabling the SearchIndexer in one `fab!` block will affect
all other `fab!` blocks which is not ideal as we may be indexing stuff
for search when we don't need to.
It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
With the addition of `PostSearchData#private_message`, a partial
index consisting of only search data from regular posts can be created.
The partial index helps to speed up searches on large sites since PG
will not have to do an index scan on the entire search data index which
has shown to be a bottle neck.
