Reconsider the review system of Gitploy.

[noahingh]

We should provide some features to enhance the review system.

Note

When I started to design the review system, I thought it was reasonable to deploy automatically after approval like GitHub. But for Gitploy, it is not feasible because Gitploy has the validation of GitHub deployment API, which can fail to deploy automatically. So we should deploy it manually.

Todo

• Change to select reviewers into static reviewers #201
• Change UI to leave the comment with approval. #197