Merge pull request rails#50731 from javierav/create-table-doc

Document passing Hash as `:id` option to `create_table` [skip ci]

Author: fatkodima

activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb

@@ -187,6 +187,9 @@ def primary_key(table_name)
       #   Join tables for {ActiveRecord::Base.has_and_belongs_to_many}[rdoc-ref:Associations::ClassMethods#has_and_belongs_to_many] should set it to false.
       #
       #   A Symbol can be used to specify the type of the generated primary key column.
+      #
+      #   A Hash can be used to specify the generated primary key column creation options.
+      #   See {add_column}[rdoc-ref:ConnectionAdapters::SchemaStatements#add_column] for available options.
       # [<tt>:primary_key</tt>]
       #   The name of the primary key, if one is to be added automatically.
       #   Defaults to +id+. If <tt>:id</tt> is false, then this option is ignored.