Improve Google Play authentication docs

[svzi]

@nprail As already stated in #15, the flow for creating the service account has changed a bit. There is no rule Release manager anymore, or I'm unable to find it... I'm unable to get it going, it says ERROR: Forbidden.

Any help would be really much appreciated!

[nprail]

Hmm, I'll try going through the flow and make sure the docs are up-to-date.

I think those instructions probably need a complete rewrite. I've only adapted them from the original playup instructions a few times and I think the process has significantly changed since.

[svzi]

@nprail That would be really helpful, because this lib seems to be very useful and I would like to give it a try!

[nprail]

@svzi Looks like there is still a Release Manager role but the docs on the README don't make it clear that the Release Manager role can only be found in the Google Play Console, not in the Google Developers Console... which is, in fact, different...

I don't believe the service account needs any permissions in the Google Developers Console.

Once you create the Google Developers Console project, service account, and key, you have to go back the the Google Play Console and give the service account the Release Manager role there.

Let me know if that works. My instructions might be a bit off because I already have it setup. The first time instructions might be a little different...

[svzi]

@nprail Thanks for your comment, I will have another look at it as soon as I've prepared my next version. I've managed to create a new service account user and assigned the Release manager role via the Google Play Console. But I haven't tried if everything works.

[stephan-nordnes-eriksen]

FYI: I had to put the Service Account Permissions to be Service Account User in order for the service account to show up in the Google Play Console. More info on stackoverflow