def get_current_table_name
      [self.old_name, self.new_name].each do |name|
        return name.to_s if self.table_exists?(name)
      end
      # raise exception if we don't have a valid table
      self.raise_no_table_error
    end
def get_current_table_name
      [self.old_name, self.new_name].each do |name|
        return name.to_s if self.table_exists?(name)
      end
      # raise exception if we don't have a valid table
      self.raise_no_table_error
    end
Constructor - sets up the record and tries to connect to
 the correct database

 @param  klass [Class] Class whose table we are renaming
 @param  old_name [String, Symbol] The old table name
 @param  new_name [String, Symbol] The new table name


 Returns the name of the table that currently exists of our
 two options (old or new)

 @return [String] The name of the existing table