Fix Chat.php bug

CONTRIBUTING.md

@@ -11,4 +11,15 @@ Which should give you no output, indicating that there are no coding standard er
 
     phpunit
 
-Which should give you no failures or errors. You can ignore any skipped tests as these are for external tools.
+Which should give you no failures or errors. You can ignore any skipped tests as these are for external tools.
\ No newline at end of file
+
+Pushing
+-------
+
+Development is based on the git flow branching model (see http://nvie.com/posts/a-successful-git-branching-model/ )
+If you fix a bug please push in hotfix branch.
+If you develop a new feature please create a new branch.  
+
+Version
+-------
+Version number: 0.#version.#hotfix

src/Entities/Chat.php

@@ -45,7 +45,11 @@ class Chat extends Entity
 
     public function isSingleChat()
     {
-        return ! $this->isGroupChat();
+        if ($this->id > 0) {
+            return true;
+        } else {
+            return false;
+        }
     }
     public function getId()
     {

src/Telegram.php

@@ -30,7 +30,7 @@ class Telegram
      *
      * @var string
      */
-    protected $version = '0.0.16';
+    protected $version = '0.16.0';
 
     /**
      * Telegram API key