code: func GetToken(uaaURL, opsManagerUsername, opsManagerPassword, clientID, clientSecret, grantType string) (token string, err error) {
  	var res *http.Response
  	params := url.Values{
  		"grant_type":    {grantType},
  		"response_type": {"token"},
  		"username":      {opsManagerUsername},
  		"password":      {opsManagerPassword},
  		"client_id":     {clientID},
  		"client_secret": {clientSecret},
  	}
  	tokenURL := fmt.Sprintf("%s/oauth/token", uaaURL)
  	tr := &http.Transport{
  		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
  	}
  	client := &http.Client{Transport: tr}
  
  	if res, err = client.PostForm(tokenURL, params); err == nil && res.StatusCode == http.StatusOK {
  		var body []byte
  
  		if body, err = ioutil.ReadAll(res.Body); err == nil {
  			t := new(Token)
  
  			if err = json.Unmarshal(body, &t); err == nil {
  				token = t.AccessToken
  			}
  		}
  	} else if res != nil && res.StatusCode != http.StatusOK {
  		body, _ := ioutil.ReadAll(res.Body)
  		err = errors.New(string(body))
  	}
  	return
  }
docs: //GetToken -