Add support for PostgreSQL operator classes to add_index

Add support for specifying non-default operator classes in PostgreSQL
indexes. An example CREATE INDEX query that becomes possible is:

    CREATE INDEX users_name ON users USING gist (name gist_trgm_ops);

Previously it was possible to specify the `gist` index but not the
custom operator class. The `add_index` call for the above query is:

    add_index :users, :name, using: :gist, opclasses: {name: :gist_trgm_ops}

1 files changed, 1 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
index 66f7d29886..8cb2851557 100644
--- a/activerecord/lib/active_record/schema_dumper.rb
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -189,6 +189,7 @@ HEADER
         index_parts << "where: #{index.where.inspect}" if index.where
         index_parts << "using: #{index.using.inspect}" if !@connection.default_index_type?(index)
         index_parts << "type: #{index.type.inspect}" if index.type
+        index_parts << "opclass: #{index.opclass.inspect}" if index.opclass.present?
         index_parts << "comment: #{index.comment.inspect}" if index.comment
         index_parts
       end