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, 3 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index be2f625d74..b66009bdc6 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -6,7 +6,7 @@ module ActiveRecord
     # this type are typically created and returned by methods in database
     # adapters. e.g. ActiveRecord::ConnectionAdapters::MySQL::SchemaStatements#indexes
     class IndexDefinition # :nodoc:
-      attr_reader :table, :name, :unique, :columns, :lengths, :orders, :where, :type, :using, :comment
+      attr_reader :table, :name, :unique, :columns, :lengths, :orders, :where, :type, :using, :opclass, :comment
 
       def initialize(
         table, name,
@@ -17,6 +17,7 @@ module ActiveRecord
         where: nil,
         type: nil,
         using: nil,
+        opclass: {},
         comment: nil
       )
         @table = table
@@ -28,6 +29,7 @@ module ActiveRecord
         @where = where
         @type = type
         @using = using
+        @opclass = opclass
         @comment = comment
       end
     end