Developer Journey with Buildpacks

I never can get GKE deployments to work for my personal apps or for your examples/ apps:

I tried to use your `samples/ruby/` helloworld in ruby.
Build beautifully but when it tries to run on GKE it fails miserably.
My kubecontext is picjked up perfectly so it KNOWS where to push, it seems to fail to pull the images.
I have a feeling there are two problems here:

1. the IMAGE PUSH functionality is not there yet [i might be wrong]
2. The image pushed, even if there (I was able to achieve this manually), the GKE cluster doesn't see the image.

It would be great to have some public docs on how to achieve a helloworld Ruby one-liner from ZERO to GKE with skaffold (without using Cloud Deploy, I mean).

## repro

```
$ git clone https://github.com/GoogleContainerTools/skaffold/
cd skaffold/examples/ruby
$ skaffold dev
Listing files to watch...
- ruby-example
Generating tags...
- ruby-example -> ruby-example:bab12d1
Checking cache...
- ruby-example: Found Locally
Tags used in deployment:
- ruby-example -> ruby-example:30e8e53bfce4adf946738eb6a5fe8dafa71b4e6ba098161abf9a47e832f4039c
Starting deploy...
- service/ruby created
- deployment.apps/ruby created
Waiting for deployments to stabilize...
- deployment/ruby: container ruby is waiting to start: ruby-example:30e8e53bfce4adf946738eb6a5fe8dafa71b4e6ba098161abf9a47e832f4039c can't be pulled
- pod/ruby-5c4948979f-dfmh2: container ruby is waiting to start: ruby-example:30e8e53bfce4adf946738eb6a5fe8dafa71b4e6ba098161abf9a47e832f4039c can't be pulled
- deployment/ruby failed. Error: container ruby is waiting to start: ruby-example:30e8e53bfce4adf946738eb6a5fe8dafa71b4e6ba098161abf9a47e832f4039c can't be pulled.
Cleaning up...
- service "ruby" deleted
- deployment.apps "ruby" deleted
1/1 deployment(s) failed
```