added managing of logrotate.conf  (#6)

* added managing of logrotate.conf for possibility enable globally compress or change keep period

* add missed file

* add config section to readme

* renamed variable for better representation, old name was a bit confusing
diff --git a/README.rst b/README.rst
index ad9cdbb..84984ce 100644
--- a/README.rst
+++ b/README.rst
@@ -52,6 +52,19 @@
               - compress
               - postrotate: "reload rsyslog >/dev/null 2>&1 || true"
 
+Change parameters in main logrotate.conf file:
+
+.. code-block:: yaml
+
+    logrotate:
+      server:
+        enabled: true
+        global_conf:
+          compress: true
+          rotate: daily
+          keep_rotate: 6
+          dateext: true
+
 Cross-formula relationship
 ==========================