Update randomGeneration method

Grid.java

@@ -172,7 +172,7 @@ public class Grid implements Iterable<Cell> {
      */
  
     void randomGeneration(Random random) {
-        boolean [][] randomState = new boolean[getNumberOfRows()][getNumberOfColumns()];
+        boolean [][] randomState = new boolean[numberOfRows][numberOfColumns];
         for (int i = 0; i < randomState.length; i++) {
             Arrays.fill(randomState[i], random.nextBoolean());
         }