login.go

func (a *Auth) Login(email, password string) string {
	url, err := GetURL("/api/login")
	if err != nil {
		return err.Error()
	}
	b := bytes.NewBufferString(`{"email":"` + email + `", "password":"` + password + `"}`)
	req, err := http.NewRequest("POST", url, b)
	if err != nil {
		return err.Error()
	}

	client := NewClient(&http.Client{})
	response, err := client.Do(req)
	if err != nil {
		httpEr := err.(*httpErr.HTTPError)
		return httpEr.Message
	}

	var token = map[string]interface{}{}
	parseBody(response.Body, &token)
	writeToken(token["token_type"].(string) + " " + token["token"].(string))
	return "Welcome! You've signed in successfully."
}