Update docs.

Author: dlorenc

docs/contributors/adding_a_dependency.md

@@ -1,50 +1,7 @@
 #### Adding a New Dependency
-Minikube uses `Godep` to manage vendored dependencies.
-`Godep` can be a bit finnicky with a project with this many dependencies.
-Here is a rough set of steps that usually works to add a new dependency.
+Minikube uses `dep` to manage vendored dependencies.
 
-1. Make a clean GOPATH, with minikube in it.
-  This isn't strictly necessary, but it usually helps.
+See the `dep` [documentation](https://golang.github.io/dep/docs/introduction.html) for installation and usage instructions.
 
-  ```shell
-  mkdir -p $HOME/newgopath/src/k8s.io
-  export GOPATH=$HOME/newgopath
-  cd $HOME/newgopath/src/k8s.io
-  git clone https://github.com/kubernetes/minikube.git
-  cd minikube
-  ```
-  
-1. Install the package versions specified in Godeps/Godeps.json
-  ```shell
-  godep restore ./...
-  ```
-  NOTE:  If you encounter a HTTP 301 error, you may need to set the following:
-  `git config --global http.https://gopkg.in.followRedirects true`
-  
-1. `go get` your new dependency.
-  ```shell
-  go get mynewdepenency
-  ```
-
-1. Use it in code, build and test.
-
-1. Import the dependency from GOPATH into vendor/
-  ```shell
-  godep save ./...
-  ```
-
-  NOTE:  godep seems to have an issue with not recovering files in `vendor/golang.org/x/sys/windows/`
-  IF you plan on committing your updated dependencies, make sure not to remove these files in your commit
-  
-
-  If it is a large dependency, please commit the vendor/ directory changes separately.
-  This makes review easier in GitHub.
-  
-  NOTE: We have recently added a deprecation message regarding boot2docker.  Make sure that this deprecation message ends up in the vendored code at `/vendor/github.com/docker/machine/libmachine/provision/boot2docker.go`: [https://github.com/kubernetes/minikube/blob/master/vendor/github.com/docker/machine/libmachine/provision/boot2docker.go#L220](https://github.com/kubernetes/minikube/blob/master/vendor/github.com/docker/machine/libmachine/provision/boot2docker.go#L220)
-
-  ```shell
-  git add vendor/
-  git commit -m "Adding dependency foo"
-  git add --all
-  git commit -m "Adding cool feature"
-  ```
+If you are introducing a large dependency change, please commit the vendor/ directory changes separately.
+This makes review easier in GitHub.