Add gogs support

[guyzmo]

[pyhedgehog]

If there are no objections I'm going to implement this one.

[guyzmo]

I got no objections, don't hesitate to ask for my help on anything. I wanted to work on it recently, as I started pushing to a friend's gogs, but I already got my hands full with both the gitlab and bitbucket integrations.
I'm also available on freenode on the channel #git-repo so please come and never hesitate to discuss the project.

[pyhedgehog]

@guyzmo, I have) first version of code: #82
I have a question:
How I'm supposed to implement tests? Current tests (for other services) not working in my environment...

[guyzmo]

for the tests, @pyhedgehog, please come back on IRC so we can discuss quickly what's going wrong.

[pyhedgehog]

Just to log here results of our discussion:

1. New version of PR should use third-party library (possibly gogs-client).
2. There are several most wanted features in gogs and gogs-client:
   • fork api (gogs#3979, gitea#477)
   • pulls api (gogs#2253, done in gitea#248)
   • token api (in client) (gogs_client#2)
   • repository listing api (not only for current users and orgs) (gogs#3984, gitea#494)
3. Features for proxy, private and ssl_verify should be implemented in service-independent manner.
4. Test should be first-class thing. 👍

[guyzmo]

for the feature set, go by babysteps:

1. implement first the already working features, like you first did (clone, create, delete, open, list) and consider that the user can copy/paste the token in the configuration file
2. implement the token API as a second step, the best way would be for you to send a PR to gogs-client for them to integrate it, so then git-repo can merge it in!
3. add the extra stuff we might want to have… You could make a PR to gogs to integrate the fork API, we can 🤞 that PR api lands soon… or you could implement some web scrapping (either in gogs-client or in a third part library extending gogs-client) to support those features.

About the configuration features:

• ssl_verify is already implemented and I'm merging it in develop, just look for self.insecure on RepositoryService,
• proxy support is a good thing to have (using the .gitconfig proxy setting), and I believe it's a good case for a new issue and PR, adding it for the four services.
• private should be a command line argument git gogs foo/bar create --private. And there's already an issue to discuss default configuration implementation, but it's not a priority currently.

About the tests, I did my best to make them easy to write and run, of course I'm around if you need any help.

[guyzmo]

FYI, I actually just checked with a gogs install, I believe it's possible to make a fork, given that the token auth works for this use case:

if you make a POST request with form data containing:

• uid → id of the new owner, i.e. current user
• repo_name → new name of the repository
• description → description of what is that repository

to the URL: /repo/fork/{id of the repository to fork} that should work!

N.B.: I believe there's a visibility parameter, but for my tests, I couldn't check as I was forking a private repository.