Added docs for #columns on some adapters

activerecord/lib/active_record/connection_adapters/mysql_adapter.rb

@@ -626,6 +626,7 @@ module ActiveRecord
         indexes
       end
 
+      # Returns an array of +MysqlColumn+ objects for the table specified by +table_name+.
       def columns(table_name, name = nil)#:nodoc:
         sql = "SHOW FIELDS FROM #{quote_table_name(table_name)}"
         columns = []

activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb

@@ -244,6 +244,7 @@ module ActiveRecord
         end
       end
 
+      # Returns an array of +SQLiteColumn+ objects for the table specified by +table_name+.
       def columns(table_name, name = nil) #:nodoc:
         table_structure(table_name).map do |field|
           case field["dflt_value"]