Added new prefix in "Adding a consumer to a consumer group" (#471)

* added new prefix in  Adding a consumer to a consumer group

* added new prefix in  Adding a consumer to a consumer group

* added active voice

* replaced in a client application to in your consumer application

* added a comma

Author: fmcdonal

docs/kafka/consumer-configuration-kafka/README.adoc

@@ -139,10 +139,13 @@ sasl.jaas.config=org.apache.kafka.common.security.plain.PlainLoginModule require
 == Adding a consumer to a consumer group
 
 [role="_abstract"]
+To create a consumer group, you specify a consumer group ID in your consumer application. You do *not* create consumer groups in the {product-kafka} web console, or using the CLI.
+
 A group ID is required for a consumer to be able to join a consumer group.
 The group ID is the name of the consumer group.
 When you configure a consumer client application to access Kafka, you assign a group ID to associate it with a consumer group.
 All consumers with the same group ID belong to the consumer group with that ID.
+
 Consumer groups connected to a Kafka instance are displayed in the {product-kafka} web console.
 
 .Procedure