Versions constants and fix composer instruction

README.md

@@ -15,7 +15,7 @@ Use [API documentation](http://retailcrm.github.io/api-client-php)
 
 2) Run into your project directory:
 ```bash
-composer require retailcrm/api-client-php 5.* --no-dev
+composer require retailcrm/api-client-php ~5.0
 ```
 
 If you have not used `composer` before, include autoloader into your project.

README.ru.md

@@ -15,7 +15,7 @@ PHP-клиент для работы с [retailCRM API](http://www.retailcrm.ru/
 
 2) Выполните в папке проекта:
 ```bash
-composer require retailcrm/api-client-php 5.*  --no-dev
+composer require retailcrm/api-client-php ~5.0
 ```
 
 В конфиг `composer.json` вашего проекта будет добавлена библиотека `retailcrm/api-client-php`, которая установится в папку `vendor/`. При отсутствии файла конфига или папки с вендорами они будут созданы.
@@ -32,7 +32,7 @@ require 'path/to/vendor/autoload.php';
 $client = new \RetailCrm\ApiClient(
     'https://demo.retailcrm.ru',
     'T9DMPvuNt7FQJMszHUdG8Fkt6xHsqngH',
-    'v5'
+    \RetailCrm\ApiClient::V5
 );
 
 try {
@@ -67,7 +67,7 @@ if ($response->isSuccessful()) {
 $client = new \RetailCrm\ApiClient(
     'https://demo.retailcrm.ru',
     'T9DMPvuNt7FQJMszHUdG8Fkt6xHsqngH',
-    'v4'
+    \RetailCrm\ApiClient::V4
 );
 
 try {

lib/RetailCrm/ApiClient.php

@@ -34,6 +34,10 @@ class ApiClient
     public $request;
     public $version;
 
+    const V3 = 'v3';
+    const V4 = 'v4';
+    const V5 = 'v5';
+
     /**
      * Init version based client
      *
@@ -43,18 +47,18 @@ class ApiClient
      * @param string $site    site code
      *
      */
-    public function __construct($url, $apiKey, $version = 'v5', $site = null)
+    public function __construct($url, $apiKey, $version = self::V5, $site = null)
     {
         $this->version = $version;
 
         switch ($version) {
-            case 'v5':
+            case self::V5:
                 $this->request = new ApiVersion5($url, $apiKey, $version, $site);
                 break;
-            case 'v4':
+            case self::V4:
                 $this->request = new ApiVersion4($url, $apiKey, $version, $site);
                 break;
-            case 'v3':
+            case self::V3:
                 $this->request = new ApiVersion3($url, $apiKey, $version, $site);
                 break;
         }