update install doc

docs/10_Introduction/10_Installation_on_a_server.md

 # Installation of CISERVER #
 
-## Installation ##
+You can install the CISERVER on your own host. You need full access to the system - it won't run on a shared hosting.
 
+## Apache Httpd + PHP ##
+
+Install an Apache httpd and enablethese modules.
+
+- rewrite
+- proxy + proxy_fcgi (or proxy_http) for a proxy
+- socache_shmcb (on Debian for ssl connections)
+
+For PHP 8.1 we need these packages
+
+- php-fpm
+- php-curl
+- php-intl
+- php-mbstring
+- php-ldap
+- php-sqlite3
+- php-xml
+
+## Other required tools ##
+
+These commandline tools must be installed.
+
+- ssh
+- rsync
+- git
+
+## Get sources ##
+
+Extract the repository in `/var/www/ciserver.example.org`. 
+You can download the archive from the git repository or use `git clone`.
+
+```txt
+cd /var/www
+git clone https://git-repo.iml.unibe.ch/iml-open-source/imldeployment.git
+mv imldeployment ciserver.example.com
+```
+
+The directory `/var/www/ciserver.example.com` is called approot in further documentation.
+
+## Update virtual host config ##
+
+Set the document root to the subdir `public_html`.
+We need two rewrite rules to redirect requests.
+
+```txt
+...
+DocumentRoot "/var/www/ciserver.example.com/public_html"
+
+<location "/deployment/">
+  RewriteEngine on
+  RewriteCond %{REQUEST_FILENAME} !-f
+  RewriteRule ^(.*)$ index.php [QSA,L]
+</Location>
+
+<Location "/api/">
+  RewriteEngine on
+  RewriteCond %{REQUEST_FILENAME} !-f
+  RewriteRule ^(.*)$ index.php [QSA,L]
+</Location>
+...
+```
+
+## Create Configs
+
+In `[approot]/config/` copy the 2 *.dist files to the same filename but without ".dist".
+
+## Create data structure and tmp
+
+The aplication works with 
+
+- a data directory /var/imldeployment
+- a tmp directory /var/tmp/imldeployment
+
+If you use ansible you can use this snippet.
+
+```txt
+- name: extra appdirs
+  become: yes
+  become_user: root
+  hosts: ciserver
+
+  tasks:
+    - name: Create CI SERVER base dirs
+      file:
+        path: '{{ item }}'
+        mode: 0750
+        owner: www-data
+        group: www-data
+        state: directory
+      loop:
+        - '/var/tmp/imldeployment'
+        - '/var/imldeployment'
+        - '/var/imldeployment/data'
+        - '/var/imldeployment/data/database'
+        - '/var/imldeployment/data/projects'
+        - '/var/imldeployment/data/sshkeys'
+        - '/var/imldeployment/build'
+        - '/var/imldeployment/defaults'
+        - '/var/imldeployment/packages'
+        - '/var/imldeployment/packages/_files'
+```
+
+## Enable shell for Apache service user ##
+
+The service user of the webservice needs to execute commands with php function exec. By default this user has set nologin as shell - this muust be changed to `bin/bash`.
+
+Remark: the username can differ from distribution to distribution. Maybe it is "apache" or "wwwrun" on your system.
+
+In the /etc/passwd edit the line of "www-data":
+
+```txt
+...
+www-data:x:33:33:www-data:/home/www-data:/bin/bash
+...
+```
+
+It can be a good idea to switch the $HOME from /var/www to the standard directory for users `/home/wwww-data` too.
+
+As Ansible snippet (remark: changing $HOME works if the user has no process - maybe you need to stop php-fpm and apache service)
+
+```txt
+    - name: give a shell to www-data
+      ansible.builtin.user:
+        name: www-data
+        home: /home/www-data
+        shell: /bin/bash
+```
+
+## First check
+
+Open `check-config.php`in the webroot, i.e. <https://ciserver.example.com/check-config.php>.