def fetch_commit(commit_id)
      found = commits.find do |commit|
        commit["sha"] == commit_id
      end
      if found
        stringify_keys_deep(found.to_hash)
      else
        # cache miss; don't add to @commits because unsure of order.
        check_github_response do
          commit = @client.commit(user_project, commit_id)
          commit = stringify_keys_deep(commit.to_hash)
          commit
        end
      end
    end
def fetch_commit(commit_id)
      found = commits.find do |commit|
        commit["sha"] == commit_id
      end
      if found
        stringify_keys_deep(found.to_hash)
      else
        # cache miss; don't add to @commits because unsure of order.
        check_github_response do
          commit = @client.commit(user_project, commit_id)
          commit = stringify_keys_deep(commit.to_hash)
          commit
        end
      end
    end
Fetch commit for specified event

 @param [String] commit_id the SHA of a commit to fetch
 @return [Hash]