docker docs

refs https://github.com/goreleaser/goreleaser/issues/320

docs/110-snapcraft.md

@@ -1,5 +1,5 @@
 ---
-title: Snapcraft
+title: Snapcraft packaging
 ---
 
 GoReleaser can generate `snap` packages. [Snaps](http://snapcraft.io/) are a

docs/130-docker.md

@@ -0,0 +1,57 @@
+---
+title: Docker Support
+---
+
+Since [v0.31.0](https://github.com/goreleaser/goreleaser/releases/tag/v0.31.0),
+[GoReleaser](https://github.com/goreleaser/goreleaser) support building and
+pushing Docker images.
+
+## How it works
+
+You can declare multiple Docker images. They will be matched against your
+the binaries generated by your `builds` section.
+
+If you have only one `build` setup, the config is as easy as adding the
+name of your image to your `.goreleaser.yml`:
+
+```yaml
+dockers:
+  - image: user/repo
+```
+
+You also need to create a `Dockerfile` in your repo root folder:
+
+```dockerfile
+FROM scratch
+COPY mybin /
+ENTRYPOINT ["/mybin"]
+```
+
+This config will build and push a docker image named `user/repo:tagname`.
+
+## Customization
+
+Of course, you can customize a lot of things out of this:
+
+```yaml
+# .goreleaser.yml
+dockers:
+  # You can have multiple Docker images
+  -
+    # GOOS of the built binary that should be used
+    goos: linux
+    # GOARCH of the built binary that should be used
+    goarch: amd64
+    # GOARM of the built binary that should be used
+    goarm: ''
+    # Name of the built binary that should be used
+    binary: mybinary
+    # Docker image name
+    image: myuser/myimage
+    # Path to the Dockerfile (from the project root)
+    dockerfile: Dockerfile
+```
+
+These settings should allow you to generate multiple docker images, using
+multiple `FROM` statements, for example, as well generate one image for
+each binary in your project.