code: function(tableName, columnName, callback) {
      var cqlString = util.format('ALTER TABLE %s DROP %s', tableName, columnName);
      return this.runSql(cqlString, callback).nodeify(callback);
    }
docs: Remove a column form an existing table
  
  @param string tableName - The name of the table to be altered
  @param string columnName - Name of the column to be removed
  @param callback