class ActiveRecord::Schema

end
...
ActiveRecord::Schema.define(version: 20380119000001) do

about the current schema (currently, only the schema's version):
The +info+ hash is optional, and if given is used to define metadata

+add_index+, etc.).
database definition DSL to build up your schema (+create_table+,
adapter are available within the block, so you can easily use the
Eval the given block. All methods available to the current connection

def self.define(info={}, &block)
  new.define(info, &block)
end