Reorder broker docs; add reference to gcp broker (#2449)

* Reorder broker docs; add reference to gcp broker

* Address comments

* Update relative links

docs/eventing/broker/README.md

@@ -1,9 +1,3 @@
----
-title: "Broker and Trigger"
-weight: 20
-type: "docs"
----
-
 Broker and Trigger are CRDs providing an event delivery mechanism that hides the
 details of event routing from the event producer and event consumer.
 
@@ -18,7 +12,7 @@ Broker).
 There can be different classes of Brokers providing different kinds
 of semantics around durability of events, performance, etc. The Broker that is
 part of the Knative Eventing repo is used for these examples, it uses Knative
-[Channels](./channels/) for delivering events. You can read more details about
+[Channels](../channels/) for delivering events. You can read more details about
 [Channel Based Broker](./channel-based-broker.md). Simple example showing a `Broker`
 where the configuration is specified in a `ConfigMap` config-br-default-channel,
 which uses `InMemoryChannel`:
@@ -193,7 +187,7 @@ types, sources (or any other CloudEvents attribute), and subscribers.
 
 ### Emitting Events using Ping Source
 
-Knative Eventing comes with a [Ping Source](./samples/ping-source/README.md) which
+Knative Eventing comes with a [Ping Source](../samples/ping-source/README.md) which
 emits an event on a configured schedule. For this we'll configure it to emit
 events once a minute, saying, yes, you guessed it `Hello World!`.
 

docs/eventing/broker/_index.md

@@ -0,0 +1,8 @@
+---
+title: "Broker and Trigger"
+weight: 60
+type: "docs"
+showlandingtoc: "true"
+---
+
+{{% readfile file="README.md" %}}

docs/eventing/broker/alternate/README.md

@@ -0,0 +1,8 @@
+In the Knative Eventing ecosystem, alternate Broker implementations are welcome as long as they
+respect the [Broker Conformance Spec](https://github.com/knative/eventing/blob/master/docs/spec/broker.md).
+
+Below is a list of brokers provided by the community or vendors in addition to the default broker
+implementations provided by Knative Eventing.
+
+## GCP Broker
+The GCP Broker is optimized for running in GCP. For more details, refer to the [doc](https://github.com/google/knative-gcp/blob/master/docs/install/install-gcp-broker.md).

docs/eventing/broker/alternate/_index.md

@@ -0,0 +1,7 @@
+---
+title: "Alternate Brokers"
+weight: 60
+type: "docs"
+---
+
+{{% readfile file="README.md" %}}

docs/eventing/broker/channel-based-broker.md

@@ -8,7 +8,7 @@ NOTE: This doc assume the shared Knative Eventing components are installed in th
 namespace. If you installed the shared Knative Eventing components in a different namespace, replace
 `knative-eventing` with the name of that namespace.
 
-Knative provides a `Broker` implementation that uses [Channels](./channels/) for
+Knative provides a `Broker` implementation that uses [Channels](../channels/) for
 event routing. You will need to have a Channel provider installed, for example
 InMemoryChannel (for development purposes), Kafka, Nats, etc. You can choose from
 list of [available channels](https://knative.dev/docs/eventing/channels/channels-crds/)

docs/eventing/broker/mt-channel-based-broker.md

@@ -10,7 +10,7 @@ namespace. If you installed the shared Knative Eventing components in a differen
 Multi Tenant Channel Based Broker.
 
 Knative provides a Multi Tenant `Broker` implementation that uses
-[Channels](./channels/) for event routing. You will need to have a Channel provider
+[Channels](../channels/) for event routing. You will need to have a Channel provider
 installed, for example InMemoryChannel (for development purposes), Kafka, Nats, etc. You can choose from
 list of [available channels](https://knative.dev/docs/eventing/channels/channels-crds/)