Add public: Boolean and collaboratorIds: String[] to the Repo model, enable inviting collaborators feature and public-shared repos. Probably need to run:

npx prisma migrate dev --name init

in API container

Updates

1. Load both your own repos and the repos where you work as a collaborator, tagged with public or private.
2. For your own private repos, show a button for sharing

3. Prompt a window when sharing, enter the email address, then the collaborator can get the repo in "shared repos" section.

4. Alert an error message when

• The user doesn't have the privilege to share
• No user is signed up with this email
• The invited user is the owner or one of their collaborators invited before.
• The repo is public

5. Also, an option in Right-click Menu in Repo page, no need to go back the homepage

Works in the future or on the way

• Now, users can't access a private repo in which they are neither owners nor collaborators. But it won't show the error, it just keeps loading. I may fix it with explicit error message later. (ETA 1 day)
• The access feature seems not in a fine-grained. Anyone can access a public repo and edit anything in it. It's terrible. We may consider separating the read and write access individually for the public ones. Besides, even someone hasn't logged in is still supposed to read any public repos. (ETA 3 days ~ 1 week)
• For those read-only public repos, we should allow fork/clone feature from unauthenticated users. Then collaborators in a public repo can be enabled again. (ETA 1-2 weeks)
• UI improvement, I just finished the function, but it looks ugly (It depends, please give me some ideas if you have any suggestion)

close #46