Question: Do I put it in each model, right before, `multisearchable :against => [ ... ]` or should this be in a separate file? Thanks.

Answer: 
I had similar questions about how to implement PgSearch.multisearch\_options.

This is what worked for me. Hopefully it will help someone else out.

I created the Initializer `config/initializers/pg_search.rb`

```
PgSearch.multisearch_options = {
  :using => {
    :tsearch => {
      :dictionary => "english"
    }
  }
}

```

In my `application.rb` file I uncommented this line: `config.active_record.schema_format = :sql` 

Then created a migration called `rails g migration add_trigram_extension` adding the below to the migration file

```
def up
    execute "create extension pg_trgm"
end

def down
    execute "drop extension pg_trgm"
end

```

Then run `bundle exec rake db:migrate`

Restart the server

Now full text search with Stemming is working.

p.s. this worked using (PostgreSQL) 9.1.4
Okay found the answer, so I'll post it below.

I created a file called `config/initializers/pg_search.rb` which looks like:

```
PgSearch.multisearch_options = { :using => { :tsearch => { :prefix => true },
                                             :trigram => {},
                                             :dmetaphone => {} },
                                 :ignoring => :accents }

```

I don't fully understand why `:trigram => {}` works rather than just `:trigram`, but I guess that should be in another post.