Update README.md

Add docker section

README.md

@@ -88,7 +88,32 @@ make clean
 # In this example, I'm assuming you have a 64MB flash chip (60 = 64 - 4)
 make -j8 EXTFLASH_SIZE_MB=60 EXTFLASH_OFFSET=4194304 INTFLASH_BANK=2 flash
 ```
+## Build and flash using Docker
 
+<details>
+  <summary>
+    If you are familiar with Docker and prefer a solution where you don't have to manually install toolchains and so on, expand this section and read on.    
+  </summary>  
+  To reduce the number of potential pitfalls in installation of various software, a Dockerfile is provided containing everything needed to compile and flash Custom Firmware (CFW) to your Nintendo® Game & Watch™ system. This Dockerfile is written tageting an x86-64 machine running Linux.
+
+  Steps to build and flash from a docker container (running on Linux, e.g. Archlinux or Ubuntu):
+
+  ```bash
+  # Copy the content of a docker directory from this repo. To create the image, cd to the folder where you put the files and type:
+  sudo docker build -t game-and-watch-patch:latest .
+
+  # When done, use the image to create a container with the attached docker-compose.yaml file.
+  # You have to edit the compose file and set the path to the directory with your firmware backup (volumes section of the file).
+  sudo docker compose up -d
+
+  # This will create and run a container game-and-watch-patch.
+  # The firmware backup files will be mounted into /tmp/firmware of the container.
+  # Now, go inside the container copy the backup files and proceed as described above in the Usage section.
+  sudo docker exec -it game-and-watch-patch /bin/bash
+
+  ```
+
+</details>
 
 
 # Troubleshooting/FAQ: