Added some informations to README

README.md

@@ -1,3 +1,31 @@
 # writefreelytag2rss
 
-Script to create a file containing an RSS feed based on a specific tag in writefreely.
+Script to create a file containing an RSS feed based on a specific tag in writefreely.
+
+## Rationale
+
+If you want to create an RSS feed based on a specific tag in a writefreely instance.
+
+If you go to the URL https://your.writefreely.instance/tag:fedora, you will get all the posts containing the "fedora" tag.
+At the moment a feed based on tags (like it could be on a site generated with Hugo) is not provided by writefreely.
+
+This script will generate a file containing such feed.
+
+## Usage
+
+Rename `config.cfg.example` to `config.cfg`
+
+Edit `config.cfg` accordingly.
+
+Put the Python script in a cron job or in a systemd timer.
+
+The generated file should be then served by a web server.
+
+## Required Python modules
+
+- bs4
+- datetime
+- feedgen
+- requests
+- configparser
+- sys