Add Dockerfile

Dockerfile

@@ -0,0 +1,4 @@
+FROM wiiuenv/devkitppc:20220907
+
+WORKDIR /app
+CMD make -j$(nproc)

README.md

@@ -2,13 +2,24 @@
 This a WUHB port of WUP Installer GX2 which can be found [here](https://sourceforge.net/projects/wup-installer-gx2/)
 
 ## Bulding
-To build this application you will need [wut](https://github.com/devkitPro/wut) and the following devkitPro packages:
+
+### Makefile
+To build this application using make, you will need [wut](https://github.com/devkitPro/wut) and the following devkitPro packages:
 `
 ppc-zlib ppc-libmad ppc-libogg ppc-libgd ppc-freetype ppc-libjpeg-turbo ppc-libpng ppc-libvorbisidec ppc-glm ppc-bzip2
 `
 
 Once the dependencies are installed just run `make` and use the resulting `.wuhb` file.
 
+### Dockerfile
+To build this application using docker, run the following commands:
+```shell
+docker build . -t wupgx2
+docker run -it --rm -v ${PWD}:/app wupgx2
+```
+
+You can then use the resulting `.wuhb` file.
+
 # Credits
 A big thanks goes out to [brienj](https://github.com/xhp-creations) for creating the original rpx port of WUP Installer GX2,
 and [Gary](https://github.com/GaryOderNichts) for making the Wii U controller mod version.