add root Dockerfile which will build all binaries

.dockerignore

@@ -0,0 +1 @@
+Dockerfile

Dockerfile

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+FROM golang:1.12 AS builder
+WORKDIR /app
+COPY . .
+RUN GOBIN=$(pwd)/bin CGO_ENABLED=0 GOOS=linux go install -a -installsuffix cgo ./cmd/...
+
+FROM alpine:latest
+RUN apk --no-cache add ca-certificates
+WORKDIR /app/bin
+COPY --from=builder /app/bin /app/bin
+ENV PATH="/app/bin:${PATH}"
+CMD echo "Available commands:" && ls

cmd/totp-proxy/Dockerfile

@@ -1,5 +0,0 @@
-FROM alpine
-RUN apk --update upgrade && apk add curl ca-certificates && \
-    update-ca-certificates && rm -rf /var/cache/apk/*
-ADD totp-proxy /totp-proxy
-CMD /totp-proxy