Change way to get

Using http may call issue, changet to https. More https://getcomposer.org/doc/00-intro.md#installation-linux-unix-osx

docs/guide/start-installation.md

@@ -24,7 +24,7 @@ Installing via Composer <span id="installing-via-composer"></span>
 If you do not already have Composer installed, you may do so by following the instructions at
 [getcomposer.org](https://getcomposer.org/download/). On Linux and Mac OS X, you'll run the following commands:
 
-    curl -s http://getcomposer.org/installer | php
+    curl -sS https://getcomposer.org/installer | php
     mv composer.phar /usr/local/bin/composer
 
 On Windows, you'll download and run [Composer-Setup.exe](https://getcomposer.org/Composer-Setup.exe).