Add Docker support

Dockerfile

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+FROM maven:latest AS builder
+
+# Copy the Emulator sources to the container
+COPY . .
+# Package it
+RUN mvn package && mv /target/Habbo*-with-dependencies.jar /target/Habbo.jar
+
+# Use Java 8 for running
+FROM java:8 AS runner
+
+# Copy the generated source
+COPY --from=builder /target/Habbo.jar /
+
+# Save the script to wait for the database, among running the Arcturus Emulator
+RUN echo "#!/bin/bash \n java  -jar /Habbo.jar" > /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+# Run the Emulator with Java
+ENTRYPOINT ["/entrypoint.sh"]