update readme

readme.md

 # iml-certman
 
-Wrapper for acme.sh to create Let's Encrypt certificates based on CSR files using DNS authentication
+Wrapper for **acme.sh** to create Let's Encrypt certificates based on CSR files using DNS authentication.
+It was written to create/ renew all needed certificates at a central system to deploy it from there (Ansible, Puppet, ...).
 
 source: <https://git-repo.iml.unibe.ch/open-source/iml-certman>
+license: GNU GPL 3.0 <http://www.gnu.org/licenses/gpl-3.0.html>
 
 ## Installation
 
@@ -11,16 +13,38 @@ source: <https://git-repo.iml.unibe.ch/open-source/iml-certman>
 * Make your changes by copying *dist files to file without ".dist" extension and edit
   * inc_config.sh
     * set credentials for dns api
-    * set path to acme.sh script
+    * set path to acme.sh script; the default is a relative path for the suggested contellation below.
     * optional: set custom target for generated certificates
     * optional: for testing enable Let's Encrypt stage server to prevent running into weekly limits during tests
   * templates/csr.txt
     * set location, company and department
 
-Verify setup with ``./cm.sh selftest``
+A suggested structure is having acme.sh and this wrapper below the same parent directory, i.e.
+
+```text
+/opt/letsenecrypt/
+  |
+  +-- acms.sh/
+  |     |
+  |     + acms.sh
+  |     + ...
+  |
+  +-- iml-certman/
+        |
+        +-- certs/
+        +-- csr/
+        +-- templates/
+        + cm.sh
+        + inc_config.sh
+        + ...
+```
 
 ## Usage
 
+Without any parameter it shows a help.
+
+Verify a new setup (or changes in the config) with ``./cm.sh selftest``.
+
 ```text
 
 ./cm.sh 
@@ -31,10 +55,9 @@ _______________________________________________________________________________
 
 _______________________________________________________________________________
 
-DEBUG: Using LE STAGE environment ...
+DEBUG: Using Let's Encrypt STAGE environment ...
 DEBUG: You can test and mess around. Do not use certs in production.
 
-
 HELP
 
 The basic syntax is
@@ -82,7 +105,7 @@ other ACTIONs
                 check of health with current setup and requirements.
                 This command is helpful for initial setups.
 
-DEBUG: Using LE STAGE environment ...
+DEBUG: Using Let's Encrypt STAGE environment ...
 DEBUG: You can test and mess around. Do not use certs in production.
 
 ```