Docs - adding missing refs in overview

docs/index.rst

@@ -1,17 +1,7 @@
 .. _CGRateS: http://cgrates.org
-.. _Go: http://golang.org
-.. _Docker: https://www.docker.com/
-.. _Kafka: https://kafka.apache.org/
-.. _redis: http://redis.io
-.. _mongodb: http://www.mongodb.org
-.. _api docs: https://godoc.org/github.com/cgrates/cgrates/apier
-.. _SQS: https://aws.amazon.com/de/sqs/
-.. _AMQP: https://www.amqp.org/
-.. _Asterisk: https://www.asterisk.org/
-.. _FreeSWITCH: https://freeswitch.com/
-.. _Kamailio: https://www.kamailio.org/w/
-.. _OpenSIPS: https://opensips.org/
 
+Preface
+=======
 
 Welcome to `CGRateS`_'s documentation!
 

docs/overview.rst

@@ -1,4 +1,17 @@
-.. _cgrates_features:
+.. _CGRateS: http://cgrates.org
+.. _Go: http://golang.org
+.. _Docker: https://www.docker.com/
+.. _Kafka: https://kafka.apache.org/
+.. _redis: http://redis.io
+.. _mongodb: http://www.mongodb.org
+.. _api docs: https://godoc.org/github.com/cgrates/cgrates/apier
+.. _SQS: https://aws.amazon.com/de/sqs/
+.. _AMQP: https://www.amqp.org/
+.. _Asterisk: https://www.asterisk.org/
+.. _FreeSWITCH: https://freeswitch.com/
+.. _Kamailio: https://www.kamailio.org/w/
+.. _OpenSIPS: https://opensips.org/
+
 
 
 Overview
@@ -48,6 +61,9 @@ CGRateS is capable of four charging modes:
    - Specific mode for Wholesale business processing high-throughput CDRs
    - Least CPU usage out of the four modes (fastest charging).
 
+
+.. _cgrates_features:
+
 Features
 --------