Explicit testing repo

tools/Dockerfile

@@ -1,17 +1,17 @@
 FROM alpine
 
-RUN echo "http://dl-cdn.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories && apk update
-
-RUN apk add \
+RUN apk add --no-cache \
         curl \
         docker-cli \
-        helm \
-        kubectl \
         make \
         neovim \
         python3 \
-        terraform \
         tree \
         zsh
 
+RUN apk add --no-cache --repository "http://dl-cdn.alpinelinux.org/alpine/edge/testing" \
+        helm \
+        kubectl \
+        terraform
+
 WORKDIR /root/src

tools/Makefile

@@ -3,7 +3,7 @@
 default: build run
 
 build:
-	docker-compose build
+	docker-compose build --quiet
 
 run:
 	docker-compose run --rm tools zsh