Allow easy repo management about sourced-ce

[smacker]

We can start with a flag for cli but according to my experience, it would be much more useful to filter out repositories from UI.

I run srcd-ce without forks on src-d organization. After it downloaded all the data I saw some strange data in the charts. I quickly identified that go-vitess repository is the reason. It's not marked as a fork on github but it is a fork. The point is: a user, just like me, would often identify what should be excluded only AFTER init.

[marnovo]

Brainstorming the entry points where the exclusion list could (in theory) be set:

1. Docker compose
2. CLI flag:
   1. Repo name(s) as args
   2. File(s) with repo name list as arg(s)
3. Web UI

Any other?

I assume this would have to take place before/during the init, right? So probably 1 and 2 above are more likely?

[r0mainK]

1. Docker compose: then we simply do not mount the repo(s) concerned on the volume
2. / 3. Gitbase will have to do the work after being informed, either by dropping the data from it's database if it's already launched, or adding this excluding functionality if it is not.

I don't really see any other entry points, but think this should be doable at any point, not only before or during the init, as the functionality could prove useful during data exploration.

[dpordomingo]

I'd say that my other answer fits here.