Custom index type support with :using.

1 files changed, 9 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index a26a0b54ea..26cacbde37 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -497,7 +497,14 @@ module ActiveRecord
       #
       #   CREATE UNIQUE INDEX index_accounts_on_branch_id_and_party_id ON accounts(branch_id, party_id) WHERE active
       #
-      # Note: only supported by PostgreSQL.
+      # ====== Creating an index with a specific method
+      #  add_index(:developers, :name, :using => 'btree')
+      # generates
+      #  CREATE INDEX index_developers_on_name ON developers USING btree (name) -- PostgreSQL
+      #  CREATE INDEX index_developers_on_name USING btree ON developers (name) -- MySQL
+      #
+      # Note: only supported by PostgreSQL and MySQL
+      #
       def add_index(table_name, column_name, options = {})
         index_name, index_type, index_columns, index_options = add_index_options(table_name, column_name, options)
         execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} (#{index_columns})#{index_options}"
@@ -745,7 +752,7 @@ module ActiveRecord
           index_name   = index_name(table_name, column: column_names)
 
           if Hash === options # legacy support, since this param was a string
-            options.assert_valid_keys(:unique, :order, :name, :where, :length, :internal)
+            options.assert_valid_keys(:unique, :order, :name, :where, :length, :internal, :using)
 
             index_type = options[:unique] ? "UNIQUE" : ""
             index_name = options[:name].to_s if options.key?(:name)