Refactor CI and enable auto-builds for auth

Automatic builds for auth-module on x86_64 (via Travis) and on-demand on-device for arm via publish.sh

The basic-auth module is not built or pushed upon 'tag' / 'release' of the faas repo, but it should be: https://github.com/openfaas/faas/tree/master/auth.  We also don't create on-device images for this, but should do for both armhf and arm64: https://github.com/openfaas/faas/blob/master/contrib/publish-arm.sh

This change addresses these challenges and also introduces a tagAndPush script to alleviate some of the recently introduced repetition in .travis.yml.

Signed-off-by: Richard Gee <richard@technologee.co.uk>

auth/basic-auth/Makefile

@@ -2,4 +2,4 @@ TAG?=latest
 
 .PHONY: build
 build:
-	docker build -t openfaas/basic-auth-plugin:${TAG} .
+	./build.sh ${TAG}

auth/basic-auth/build.sh

@@ -0,0 +1,27 @@
+#!/bin/sh
+set -e
+
+export arch=$(uname -m)
+export eTAG="latest-dev"
+
+if [ "$arch" = "armv7l" ] ; then
+   eTAG="latest-armhf-dev"
+elif [ "$arch" = "aarch64" ] ; then
+   eTAG="latest-arm64-dev"
+fi
+
+echo "$1"
+if [ "$1" ] ; then
+  eTAG=$1
+  if [ "$arch" = "armv7l" ] ; then
+    eTAG="$1-armhf"
+  elif [ "$arch" = "aarch64" ] ; then
+    eTAG="$1-arm64"
+  fi
+fi
+
+NS=openfaas
+
+echo Building $NS/basic-auth-plugin:$eTAG
+
+docker build -t $NS/basic-auth-plugin:$eTAG .

auth/basic-auth/push.sh

@@ -0,0 +1,27 @@
+#!/bin/sh
+set -e
+
+export arch=$(uname -m)
+export eTAG="latest-dev"
+
+if [ "$arch" = "armv7l" ] ; then
+   eTAG="latest-armhf-dev"
+elif [ "$arch" = "aarch64" ] ; then
+   eTAG="latest-arm64-dev"
+fi
+
+echo "$1"
+if [ "$1" ] ; then
+  eTAG=$1
+  if [ "$arch" = "armv7l" ] ; then
+    eTAG="$1-armhf"
+  elif [ "$arch" = "aarch64" ] ; then
+    eTAG="$1-arm64"
+  fi
+fi
+
+NS=openfaas
+
+echo Pushing $NS/basic-auth-plugin:$eTAG
+
+docker push $NS/basic-auth-plugin:$eTAG