Added build scripts

Dockerfile

@@ -0,0 +1,27 @@
+ARG BASE_IMAGE
+ARG BUILD_IMAGE=ubuntu
+
+FROM ${BUILD_IMAGE} as build
+ARG INSTALLER_URL
+ARG INSTALLER_CHECKSUM
+ARG MODPACK_ID
+ARG MODPACK_VERSION
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+        curl \
+        ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+WORKDIR /server
+RUN curl -o installer ${INSTALLER_URL} \
+    && echo "${INSTALLER_CHECKSUM}  installer" | sha256sum -c \
+    && chmod +x installer \
+    && ./installer ${MODPACK_ID} ${MODPACK_VERSION} --auto --verbose \
+    && rm installer
+
+FROM ${BASE_IMAGE} as final
+WORKDIR /server
+VOLUME [ "/server" ]
+COPY --from=build /server ./
+RUN echo "eula=true" > eula.txt
+EXPOSE 25565
+CMD [ "/bin/bash", "/server/start.sh" ]