Fixed Dockerfile for global CNet CI integration

Dockerfile

@@ -1,2 +1,20 @@
 FROM gradle:4.4.0-jdk8
+
+# For permissions issues
+USER root
+
+# Copy necessary files in /app
+COPY . /app 
+WORKDIR /app
+
+# Replace cached gradle dependencies with the ones in the repo
 COPY ./minecraft /home/gradle/.gradle/caches/minecraft
+
+# Set up the workspace at build time so the runtime doesn't have to
+RUN ./gradlew setupCIWorkspace
+
+# Entrypoint for the container is either the command passed to docker run.. 
+ENTRYPOINT [ "/bin/bash", "-l", "-c" ]
+# ..or the default command that will run the build script
+# The update_and_build.sh script is located in the ElectricalAge repo
+CMD [ "./update_and_build.sh" ]