added links to alternative ways to install Friendica to the docs

INSTALL.txt

@@ -56,6 +56,13 @@ you wish to communicate with the Diaspora network.
 	- For alternative server configurations (such as Nginx server and MariaDB
 	database engine), refer to the wiki at https://github.com/friendica/friendica/wiki
 
+This guide will walk you through the manual installation process of Friendica.
+If this is nothing for you, you might be interested in
+
+* the Friendica Docker image (https://github.com/friendica/docker) or
+* how install Friendica with YunoHost] https://github.com/YunoHost-Apps/friendica_ynh).
+
+
 2. Unpack the Friendica files into the root of your web server document area.
 
 	- If you copy the directory tree to your webserver, make sure

doc/Install.md

@@ -40,6 +40,14 @@ Requirements
 Installation procedure
 ---
 
+### Alternative Installation Methods
+
+This guide will walk you through the manual installation process of Friendica.
+If this is nothing for you, you might be interested in
+
+* the [Friendica Docker image](https://github.com/friendica/docker) or
+* how [install Friendica with YunoHost](https://github.com/YunoHost-Apps/friendica_ynh).
+
 ### Get Friendica
 
 Unpack the Friendica files into the root of your web server document area.

doc/de/Install.md

@@ -40,6 +40,14 @@ Requirements
 Installation
 ---
 
+### Alternative Wege um Friendica zu Installieren
+
+Diese Anleitung wird dir Schritt-für-Schritt zeigen wie du Friendica auf deinem Server installieren kannst.
+Falls du an automatischen Möglichkeiten interesse hast, wirf doch einen Blick auf
+
+* das [Docker image für Friendica](https://github.com/friendica/docker) oder
+* die [Installation von Friendica auf YunoHost](https://github.com/YunoHost-Apps/friendica_ynh).
+
 ### Friendica
 
 Entpacke die Friendica-Daten in das Quellverzeichnis (root) des Dokumentenbereichs deines Webservers.