すみませんこれバグってますね。
こうでどうでしょうか
```
    if validate
      admin = User.find(self.members.find_by("is_admin = true").user_id)
      github = Github.new(oauth_token: admin.github.oauth_token)
      owner, repo_name = full_name.gsub(/[[:space:]*]/, "").split("/")
      repo = github.repos.get(owner, repo_name)
      return false unless repo
      pg.full_name = repo.full_name
    else
      pg.full_name = full_name.gsub(/[[:space:]*]/, "")
    end

    pg.save
```