Changed crystal template, picked latest flask one

template/crystal/Dockerfile

@@ -0,0 +1,38 @@
+FROM crystallang/crystal:1.8.0 as builder
+
+RUN apt update \
+    && apt install -y curl \
+    && echo "Pulling watchdog binary from Github." \
+    && curl -sSL https://github.com/openfaas/faas/releases/download/0.9.6/fwatchdog > /usr/bin/fwatchdog \
+    && chmod +x /usr/bin/fwatchdog
+
+WORKDIR /home/app
+COPY . .
+
+COPY function/shard.yml shard.yml
+RUN shards install
+RUN crystal build main.cr -o handler --release
+
+FROM crystallang/crystal:1.8.0
+RUN apt install ca-certificates
+
+# Add non root user
+RUN adduser app
+RUN mkdir -p /home/app
+
+WORKDIR /home/app
+
+COPY --from=builder /usr/bin/fwatchdog   .
+COPY --from=builder /home/app/function/  .
+COPY --from=builder /home/app/handler    .
+
+RUN chown -R app /home/app
+
+USER app
+
+ENV fprocess="./handler"
+EXPOSE 8080
+
+HEALTHCHECK --interval=2s CMD [ -e /tmp/.lock ] || exit 1
+
+CMD ["./fwatchdog"]