Added first version

This is basically the [git Dockerfile][1], but extended for git-annex

[1]: https://github.com/alpine-docker/git/blob/master/Dockerfile

Dockerfile

@@ -0,0 +1,11 @@
+FROM alpine
+
+RUN apk fix && \
+    apk --no-cache --update add git git-lfs gpg less man-pages openssh patch git-annex && \
+    git lfs install
+
+VOLUME /git
+WORKDIR /git
+
+ENTRYPOINT ["git-annex"]
+CMD ["--help"]