def base_sha
      default_branch = client.repo(repo)[:default_branch]
      branches.find { |branch| branch[:name] == default_branch }[:commit][:sha]
    end
def base_sha
      default_branch = client.repo(repo)[:default_branch]
      branches.find { |branch| branch[:name] == default_branch }[:commit][:sha]
    end
Head SHA of default branch, used for creating new branches