Cleanup README

As per linter.
Add note on additional-tools.

README.md

@@ -1,7 +1,7 @@
-[![travis ci](https://travis-ci.org/heroku/heroku-buildpack-go.svg?branch=master)](https://travis-ci.org/heroku/heroku-buildpack-go)
-
 # Heroku Buildpack for Go
 
+[![travis ci](https://travis-ci.org/heroku/heroku-buildpack-go.svg?branch=master)](https://travis-ci.org/heroku/heroku-buildpack-go)
+
 ![Heroku Buildpack for Go](https://cloud.githubusercontent.com/assets/51578/15877053/53506724-2cdf-11e6-878c-e2ef60ba741f.png)
 
 This is the official [Heroku buildpack][buildpack] for [Go][go].
@@ -16,7 +16,7 @@ There's also a hello world sample app at
 
 ## Example
 
-```
+```console
 $ ls -A1
 .git
 vendor
@@ -42,6 +42,7 @@ $ git push heroku master
 
 This buildpack will detect your repository as Go if you are using either:
 
+- [dep][dep]
 - [govendor][govendor]
 - [glide][glide]
 - [GB][gb]
@@ -54,54 +55,71 @@ article][app-engine-build-constraints] for more.
 ## dep specifics
 
 The `Gopkg.toml` file allows for arbitrary, tool specific fields. This buildpack
-utilizes this feature to track build specific configuration and are encoded in
+utilizes this feature to track build specific configuration which are encoded in
 the following way:
 
-* `metadata.heroku['root-package']` (String): the root package name of the
+- `metadata.heroku['root-package']` (String): the root package name of the
   packages you are pushing to Heroku.You can find this locally with `go list -e
   .`. There is no default for this and it must be specified.
 
-* `metadata.heroku['goVersion']` (String): the major version of go you would
+- `metadata.heroku['go-version']` (String): the major version of go you would
   like Heroku to use when compiling your code: if not specified defaults to the
   most recent supported version of Go.
 
-* `metadata.heroku['install']` (Array of Strings): a list of the packages you
+- `metadata.heroku['install']` (Array of Strings): a list of the packages you
   want to install. If not specified, this defaults to `["."]`. Other common
   choices are: `["./cmd/..."]` (all packages and sub packages in the `cmd`
   directory) and `["./..."]` (all packages and sub packages of the current
   directory). The exact choice depends on the layout of your repository though.
   Please note that `./...`, for versions of go < 1.9, includes any packages in
   your `vendor` directory.
 
-* `metadata.heroku['ensure']` (String): if this is set to `false` then `dep
+- `metadata.heroku['ensure']` (String): if this is set to `false` then `dep
   ensure` is not run.
 
+- `metadata.heroku['additional-tools']` (Array of Strings): a list of additional
+  tools that the buildpack is aware of that you want it to install. If the tool
+  has multiple versions an optional `@<version>` suffix can be specified to
+  select that specific version of the tool. Otherwise the buildpack's default
+  version is chosen. Currently the only supported tool is
+  `github.com/mattes/migrate` at `v3.0.0` (also the default version).
+
+```toml
+[metadata.heroku]
+  root-package = "github.com/heroku/fixture"
+  go-version = "1.8.3"
+  install = [ "./cmd/...", "./foo" ]
+  ensure = "false"
+  additional-tools = ["github.com/mattes/migrate"]
+...
+```
+
 ## govendor specifics
 
 The [vendor.json][vendor.json] spec that govendor follows for its metadata
 file allows for arbitrary, tool specific fields. This buildpack uses this
 feature to track build specific bits. These bits are encoded in the following
 top level json keys:
 
-* `rootPath` (String): the root package name of the packages you are pushing to
+- `rootPath` (String): the root package name of the packages you are pushing to
   Heroku. You can find this locally with `go list -e .`. There is no default for
   this and it must be specified. Recent versions of govendor automatically fill
   in this field for you. You can re-run `govendor init` after upgrading to have
   this field filled in automatically, or it will be filled the next time you use
    govendor to modify a dependency.
 
-* `heroku.goVersion` (String): the major version of go you would like Heroku to
+- `heroku.goVersion` (String): the major version of go you would like Heroku to
   use when compiling your code: if not specified defaults to the most recent
   supported version of Go.
 
-* `heroku.install` (Array of Strings): a list of the packages you want to install.
+- `heroku.install` (Array of Strings): a list of the packages you want to install.
   If not specified, this defaults to `["."]`. Other common choices are:
   `["./cmd/..."]` (all packages and sub packages in the `cmd` directory) and
   `["./..."]` (all packages and sub packages of the current directory). The exact
    choice depends on the layout of your repository though. Please note that `./...`
    includes any packages in your `vendor` directory.
 
-* `heroku.additionalTools` (Array of Strings): a list of additional tools that
+- `heroku.additionalTools` (Array of Strings): a list of additional tools that
   the buildpack is aware of that you want it to install. If the tool has
   multiple versions an optional `@<version>` suffix can be specified to select
   that specific version of the tool. Otherwise the buildpack's default version
@@ -142,26 +160,26 @@ latest released minor version in that series. Setting `$GOVERSION` to a specific
 minor Go version will pin Go to that version. Examples:
 
 ```console
-$ heroku config:set GOVERSION=go1.9   # Will use go1.9.X, Where X is that latest minor release in the 1.9 series
-$ heroku config:set GOVERSION=go1.7.5 # Pins to go1.7.5
+heroku config:set GOVERSION=go1.9   # Will use go1.9.X, Where X is that latest minor release in the 1.9 series
+heroku config:set GOVERSION=go1.7.5 # Pins to go1.7.5
 ```
 
 `glide install` will be run to ensure that all dependencies are properly
 installed. If you need the buildpack to skip the `glide install` you can set
 `$GLIDE_SKIP_INSTALL` to `true`. Example:
 
 ```console
-$ heroku config:set GLIDE_SKIP_INSTALL=true
-$ git push heroku master
+heroku config:set GLIDE_SKIP_INSTALL=true
+git push heroku master
 ```
 
 Installation defaults to `.`. This can be overridden by setting the
 `$GO_INSTALL_PACKAGE_SPEC` environment variable to the package spec you want the
 go tool chain to install. Example:
 
 ```console
-$ heroku config:set GO_INSTALL_PACKAGE_SPEC=./...
-$ git push heroku master
+heroku config:set GO_INSTALL_PACKAGE_SPEC=./...
+git push heroku master
 ```
 
 ## Usage with other vendoring systems
@@ -190,7 +208,7 @@ that tests have been added to the `test/run` script and any corresponding fixtur
 Requires docker.
 
 ```console
-$ make test
+make test
 ```
 
 ## Using with cgo
@@ -234,11 +252,10 @@ into the compiled executable.
 
 This buildpack also supports the testpack API.
 
-
 ## Deploying
 
 ```console
-$ make publish # && follow the prompts
+make publish # && follow the prompts
 ```
 
 ### New Go version
@@ -255,6 +272,7 @@ $ make publish # && follow the prompts
 [go]: http://golang.org/
 [buildpack]: http://devcenter.heroku.com/articles/buildpacks
 [go-linker]: https://golang.org/cmd/ld/
+[dep]: https://github.com/golang/dep
 [godep]: https://github.com/tools/godep
 [govendor]: https://github.com/kardianos/govendor
 [gb]: https://getgb.io/