remove docker hub config in favour of circleci

.docker/Dockerfile

@@ -1,6 +0,0 @@
-# vim: ft=Dockerfile
-FROM alpine:3.5
-ARG TAG
-ENV TAG ${TAG:-master}
-LABEL org.netdisco.maintainer="The Netdisco Project"
-LABEL org.netdisco.version=${TAG}

.docker/hooks/build

@@ -1,2 +0,0 @@
-#!/bin/bash
-docker build --build-arg TAG=$SOURCE_BRANCH -t $IMAGE_NAME .

.docker/hooks/post_push

@@ -1,7 +0,0 @@
-#!/bin/bash
-for url in $(echo $BUILD_TRIGGERS | sed "s/,/ /g"); do
-  curl -sL -X POST -H "Content-Type: application/json" \
-    -u "$ACCESS_TOKEN" \
-    --data "{\"tag_name\": \"$SOURCE_BRANCH\", \"target_commitish\": \"master\", \"name\": \"Netdisco $SOURCE_BRANCH\"}" \
-    $url
-done