Document using goreleaser

Signed-off-by: Joe Beda <joe.github@bedafamily.com>

.gitignore

@@ -10,6 +10,7 @@
 _obj
 _test
 _output
+dist
 
 # Architecture specific extensions/prefixes
 *.[568vq]

.goreleaser.yml

+project_name: ks
+builds:
+  - main: .
+    binary: ks
+    ldflags: -X main.version={{.Version}}
+    goos:
+      - linux
+      - darwin
+      - windows
+    goarch:
+      - amd64
+archive:
+  wrap_in_directory: true
+  format_overrides:
+    - goos: windows
+      format: zip
+  files:
+    - LICENSE
+    - README.md
+    - CHANGELOG.md
+    - CODE-OF-CONDUCT.md
+    - CONTRIBUTING.md
+release:
+  github:
+    owner: ksonnet
+    name: ksonnet
+brew:
+  github:
+    owner: INVALID
+    name: homebrew-tap
+  commit_author:
+    name: heptibot
+    email: heptibot@heptio.com
+  homepage: "https://ksonnet.io"
+  description: "The ksonnet command line utility. Manage and deploy Kubernetes applications."

CONTRIBUTING.md

@@ -106,22 +106,4 @@ To do so, run `make test` in the root of the ksonnet repo, specifying any additi
 
 ## Make a Release
 
-To make a new release, follow these instructions:
-
-1. Set a release tag (based on [semvar](http://semver.org/)):
-  ```
-  VERSION=vX.Y.Z
-  ```
-2. Build a release binary (this will set the `ks` version to `$VERSION`):
-  ```
-  make install -e VERSION=$VERSION
-  ```
-3. Add an appropriate tag. We do this via `git` (not the github UI) so that the tag is signed.  This process requires you to have write access to the real `master` branch (not your local fork).
-  ```
-  git fetch   # update
-  git tag -s -m $VERSION $VERSION origin/master
-  git push origin tag $VERSION
-  ```
-
-4. *Now* create the Github release, using the existing tag created
-   above.
+See our [release documentation](docs/release.md) for the process of creating a release.

docs/release.md

+# Releasing a new version of `ks`
+
+We use the [goreleaser](https://goreleaser.com) project to automate building and marking releases for `ks`.
+This does the following for us:
+
+1. Builds binaries across platforms and creates release tarballs/zips.
+1. [optionally] Creates a changelog based on all PRs since the last release.
+1. Creates a github release, uploading the changelog and the release archives.
+1. Updates homebrew formula to point to the new release.
+
+This is super convenient! But it is a little more involved than just running a command as we lock down our homebrew tap repo.
+
+Detailed instructions follow.
+
+## Install and configure goreleaser
+
+Follow the instructions on https://goreleaser.com for downloading and installing goreleaser.
+
+In addition to getting the utility itself installed you need to make sure that you have a github token created and set in an environment variable.
+Do this by going [here](https://github.com/settings/tokens/new) and ensure that the `repo` scope is selected.
+Take the resultant token and set it in a `GITHUB_TOKEN` environment variable.
+Multiple utilities (including `ks` itself!) will use this token so this isn't a bad thing to have set up all the time.
+Make sure you don't check this token in anywhere thought!
+
+```bash
+export GITHUB_TOKEN=<long hex number>
+```
+
+## Tag a release
+
+We use semantic versioning to tag a release.
+See [semvar](http://semver.org/).
+
+```bash
+VERSION=v0.9.0
+git tag -a $VERSION -m $VERSION
+git push origin $VERSION
+```
+
+If you have GPG signing set up for git, you can add an `-s` above to create a signed tag.
+
+## Create and clone fork of `ksonnet/homebrew-tap`
+
+You are going to have to create a PR for the updated homebrew tap file.
+As such, go to https://github.com/ksonnet/homebrew-tap and hit the "fork" button.
+
+Then do the following someplace:
+
+```
+git clone git@github.com:GITHUB_USER_NAME/homebrew-tap.git ksonnet-homebrew-tap
+cd ksonnet-homebrew-tap
+git remote add upstream git@github.com:ksonnet/homebrew-tap.git
+git fetch upstream
+```
+
+## Update your fork of `ksonnet/homebrew-tap`
+
+If your fork isn't caught up with the upstream repo you need to do this as goreleaser will write directly to github and you want to minimize merge conflicts later.
+
+```
+cd ksonnet-homebrew-tap
+git fetch upstream
+git pull
+git rebase upstream/master
+git push
+```
+
+## Copy and update .goreleaser.yml
+
+Back in the `ksonnet` directory
+
+```bash
+cp .goreleaser.yml $TMPDIR
+```
+
+Now edit `$TMPDIR/.goreleaser.yml` and update the brew section to point to your repo.
+
+## Build and push release
+
+```bash
+goreleaser --config $TEMPDIR/.goreleaser.yml
+```
+
+### [optional] Custom release notes
+
+If you want custom release notes (instead of the autogenerated ones) then create a markdown file (`$TEMPDIR/release-notes.md`) and run this instead.
+
+```bash
+goreleaser --config $TEMPDIR/.goreleaser.yml --release-notes $TEMPDIR/release-notes.md
+```
+
+At this point, if everything goes well, there should be a new release at https://github.com/ksonnet/ksonnet/releases.  Check it out and make sure it looks good.
+
+## Create PR for brew update
+
+```
+cd ksonnet-homebrew-tap
+git pull
+git commit --amend --reset-author --signoff --no-edit
+git push origin -f
+```
+
+Now go to your fork on github and create a PR for the updated brew formula