Adjust documentation

Author: borisskert

README.md

@@ -22,7 +22,7 @@ mvn package
 # Run console game
 
 ```shell script
-java -jar target/sudoku.jar
+java -Dfile.encoding=UTF-8 -jar target/sudoku.jar
 ```
 
 Game looks like:
@@ -59,4 +59,4 @@ Type in 'SOLVE' to solve the puzzle
 Column: _
 Line: _
 Value: _
-```
+```