docker: use .dockerignore to simplify Dockerfile

[nor...@perkeep.org]

https://github.com/perkeep/perkeep/commit/5bf75895b898b30ab20a4d387eced22a5dd46533

commit 5bf75895b898b30ab20a4d387eced22a5dd46533
Author: Will Norris <wi...@willnorris.com>
Date: Tue May 3 11:41:32 2022 -0700

docker: use .dockerignore to simplify Dockerfile

add Dockerfile to .dockerignore, which achieves the same effect of
quicker iteration, without having to manually add each separate file and
directory to the build image.

diff --git a/.dockerignore b/.dockerignore
index e143248..fbd3ecd 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -1,3 +1,4 @@
bin/*
tmp/*
misc/docker/release/*
+Dockerfile
diff --git a/Dockerfile b/Dockerfile
index 65ca4d5..295ddcf 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -18,22 +18,7 @@ WORKDIR /go/src/perkeep.org
COPY go.mod go.sum ./
RUN go mod download

-# Add each directory separately, so our context doesn't include the
-# Dockerfile itself, to permit quicker iteration with docker's
-# caching.
-ADD .git /go/src/perkeep.org/.git
-add app /go/src/perkeep.org/app
-ADD clients /go/src/perkeep.org/clients
-ADD cmd /go/src/perkeep.org/cmd
-ADD config /go/src/perkeep.org/config
-ADD dev /go/src/perkeep.org/dev
-ADD doc /go/src/perkeep.org/doc
-ADD internal /go/src/perkeep.org/internal
-ADD pkg /go/src/perkeep.org/pkg
-ADD server /go/src/perkeep.org/server
-ADD website /go/src/perkeep.org/website
-ADD make.go /go/src/perkeep.org/make.go
-ADD VERSION /go/src/perkeep.org/VERSION
+COPY . .

RUN go run make.go -v