use buildpacks when Dockerfile is not present

[poy]

This CL uses the heroku/buildpacks builder if a Dockerfile is not found.

fixes #43

[jamesward]

This is great! Think we should have any tests around this?

[ahmetb]

Thanks for this!
Mostly lgtm, mainly my concern in #43 and some cosmetics.

[ahmetb]

this is lgtm
hold until we figure out how we can ship pack CLI in the shell image.

[jamesward]

Going through some legal review stuff, can we move pack to /opt/pack/pack and symlink it into /usr/local/bin and also include the license in the /opt/pack dir?

[poy]

@jamesward

Going through some legal review stuff, can we move pack to /opt/pack/pack and symlink it into /usr/local/bin and also include the license in the /opt/pack dir?

done

[poy]

This is great! Think we should have any tests around this?

Discussed with @jamesward offline, we decided to punt on tests for the moment until the project is pretty structured for them.

[jamesward]

@jamesward

Going through some legal review stuff, can we move pack to /opt/pack/pack and symlink it into /usr/local/bin and also include the license in the /opt/pack dir?

done

I updated my comment after you saw it. :) Can you sub-dir it and put the pack license in that subdir?

[poy]

I updated my comment after you saw it. :) Can you sub-dir it and put the pack license in that subdir?

@jamesward Seems more likely that I didn't read it very carefully :)

Updated. PTAL

[jamesward]

This hasn't rolled out yet, but when it does, this should work:
https://console.cloud.google.com/cloudshell/editor?shellonly=true&cloudshell_image=gcr.io/cloudrun/button&cloudshell_git_repo=https://github.com/jamesward/hello-go.git&cloudshell_git_branch=buildpack

[jamesward]

This is now working!