Feature/dockerfile (#73)

* Working Dockerfile

* No need for crystal in distribution image

.dockerignore

@@ -0,0 +1,8 @@
+.*
+Dockerfile
+Makefile
+bench/
+bin/
+spec/
+
+*.html

Dockerfile

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+FROM alpine:3.8 as builder
+RUN apk add --update crystal shards openssl-dev yaml-dev libxml2-dev musl-dev
+RUN mkdir /ameba
+WORKDIR /ameba
+COPY . /ameba/
+RUN shards build --release
+
+FROM alpine:3.8
+RUN apk add --update openssl yaml pcre gc libevent libgcc
+RUN mkdir /src
+WORKDIR /src
+COPY --from=builder /ameba/bin/ameba /usr/bin/
+ENTRYPOINT [ "/usr/bin/ameba" ]