Update README.md

Author: PiroX4256

README.md

@@ -30,7 +30,7 @@ The final version must include:
 | Basic rules | [![GREEN](https://placehold.it/15/44bb44/44bb44)](https://github.com/S0NN1/ing-sw-2020-piemonti-pirovano-sonnino/tree/master/src/main/java/it/polimi/ingsw/model) |
 | Complete rules | [![GREEN](https://placehold.it/15/44bb44/44bb44)](https://github.com/S0NN1/ing-sw-2020-piemonti-pirovano-sonnino/tree/master/src/main/java/it/polimi/ingsw/model) |
 | Socket |[![GREEN](https://placehold.it/15/44bb44/44bb44)](https://github.com/S0NN1/ing-sw-2020-piemonti-pirovano-sonnino/tree/master/src/main/java/it/polimi/ingsw/server) |
-| GUI | [![YELLOW](https://placehold.it/15/ffdd00/ffdd00)](https://github.com/S0NN1/ing-sw-2020-piemonti-pirovano-sonnino/tree/master/src/main/java/it/polimi/ingsw/client/gui) |
+| GUI | [![GREEN](https://placehold.it/15/44bb44/44bb44)](https://github.com/S0NN1/ing-sw-2020-piemonti-pirovano-sonnino/tree/master/src/main/java/it/polimi/ingsw/client/gui) |
 | CLI |[![GREEN](https://placehold.it/15/44bb44/44bb44)](https://github.com/S0NN1/ing-sw-2020-piemonti-pirovano-sonnino/tree/master/src/main/java/it/polimi/ingsw/client/cli) |
 | Multiple games | [![GREEN](https://placehold.it/15/44bb44/44bb44)](https://github.com/S0NN1/ing-sw-2020-piemonti-pirovano-sonnino/blob/master/src/main/java/it/polimi/ingsw/server/Server.java)|
 | 5 Advanced Gods | [![GREEN](https://placehold.it/15/44bb44/44bb44)](https://github.com/S0NN1/ing-sw-2020-piemonti-pirovano-sonnino/tree/master/src/main/java/it/polimi/ingsw/model/player/gods/advancedgods) |