Merge pull request 'fix desezrialize' (#18) from fix into master

Reviewed-on: #18

app/src/main/java/sudoku/io/SudokuSerializer.java

@@ -243,6 +243,9 @@ public class SudokuSerializer {
 
 			Sudoku s = new Sudoku(sudokuCells, sudokuBlocks, sudokuConstraints);
 			s.setBlockWidth(sudokuJsonObject.getInt("blockWidth"));
+			for (Block block : s.getBlocks()) {
+				block.getSudokus().add(s);
+			}
 			sudokus.add(s);
 		}