Merge branch 'update-docs' into 'master'

install doc: add git clone

See merge request !94

docs/20_Installation.md

@@ -7,7 +7,26 @@
 - manual test run
 - create a cronjob
 
-## Uncompress client
+## Installation with git clone
+
+The most easy way is to use git pull.
+If you don't have / want to use git see the next chapter "Manual installation: uncompress archive".
+
+As user **root**:
+
+```shell
+# Create the directory level above
+mdir -p /opt/imlbackup/
+cd /opt/imlbackup/
+
+# Get the software into subdir "client"
+git clone https://git-repo.iml.unibe.ch/iml-open-source/iml-backup.git client
+
+# to set working directory to /opt/imlbackup/client:
+cd client
+```
+
+## Manual installation: uncompress archive
 
 To put all files into a directory i.e.