code: public Table concat(Table tableToConcatenate) {
          Preconditions.checkArgument(tableToConcatenate.rowCount() == this.rowCount(),
                  "Both tables must have the same number of rows to concatenate them.");
          for (Column<?> column : tableToConcatenate.columns()) {
              this.addColumns(column);
          }
          return this;
      }
docs: Add all the columns of tableToConcatenate to this table
  Note: The columns in the result must have unique names, when compared case insensitive
  Note: Both tables must have the same number of rows
  @param tableToConcatenate    The table containing the columns to be added
  @return                      This table