code: def create_column(self, name, type):
          
          self._check_dropped()
          if normalize_column_name(name) not in self._normalized_columns:
              self.op.add_column(self.table.name, Column(name, type), self.table.schema)
              self.table = self._update_table(self.table.name)
docs: Explicitely create a new column ``name`` of a specified type.
          ``type`` must be a `SQLAlchemy column type <http://docs.sqlalchemy.org/en/rel_0_8/core/types.html>`_.
          ::
  
              table.create_column('created_at', sqlalchemy.DateTime)