def digest_auth(user, password)
      builder.insert(0, Faraday::Request::DigestAuth, user, password)
    end
def digest_auth(user, password)
      builder.insert(0, Faraday::Request::DigestAuth, user, password)
    end
Public: Adds the digest auth middleware at the top and sets the user and
 password.

 user     - A String with the user.
 password - A String with the password.