added create organization

Author: Ha-Moham

lib/Github/Api/Organization.php

@@ -52,6 +52,20 @@ public function createRepo($organization, array $params)
     {
         return $this->post('/orgs/'.rawurlencode($organization).'/repos', $params);
     }
+    /**
+     * create organization
+     *
+     * @param string $login organization name
+     * @param string $admin  GitHub username
+     * @param string $profile_name   Optional
+     *
+     * @return array the repositories
+     */
+    public function createOrganization( array $params)
+    {
+
+        return $this->post('/admin/organizations', $params);
+    }
     /**
      * List all repositories across all the organizations that you can access.
      *