How do I explicitly specify a Model's table-name mapping in Rails?

Question

Rails >= 3.2 (including Rails 4+ and 5+):

class Countries < ActiveRecord::Base
  self.table_name = "cc"
end

Rails <= 3.1:

class Countries < ActiveRecord::Base
  self.set_table_name "cc"
  ...
end

class Countries < ActiveRecord::Base
    self.table_name = "cc"
end

In Rails 3.x this is the way to specify the table name.