Add the doc on Gateway (#2730)

* Add the doc on Gateway

Signed-off-by: Artem Zatsarynnyi <azatsary@redhat.com>

* Fix the errors reported by antora

Signed-off-by: Artem Zatsarynnyi <azatsary@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Update modules/end-user-guide/pages/idea-ultimate.adoc

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

* Apply suggestions from code review

Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

---------

Signed-off-by: Artem Zatsarynnyi <azatsary@redhat.com>
Co-authored-by: Jana Vrbkova <jvrbkova@redhat.com>

modules/end-user-guide/examples/snip_che-table-of-supported-editors.adoc

@@ -24,3 +24,10 @@
 * `latest` is the stable version.
 * `next` is the development version.
 
+| link:https://github.com/redhat-developer/devspaces-gateway-plugin/[JetBrains IntelliJ IDEA Ultimate Edition (over JetBrains Gateway)]
+|
+* `che-incubator/che-idea-server/latest`
+* `che-incubator/che-idea-server/next`
+|
+* `latest` is the stable version.
+* `next` is the development version.

modules/end-user-guide/nav.adoc

@@ -26,6 +26,7 @@
 * xref:devfile-introduction.adoc[]
 * xref:ides-in-workspaces.adoc[]
 ** xref:microsoft-visual-studio-code-open-source-ide.adoc[]
+** xref:idea-ultimate.adoc[]
 ** xref:defining-a-common-ide.adoc[]
 * xref:using-credentials-and-configurations-in-workspaces.adoc[]
 ** xref:mounting-secrets.adoc[]

modules/end-user-guide/pages/idea-ultimate.adoc

@@ -0,0 +1,64 @@
+[id="idea-ultimate"]
+= Connecting JetBrains IntelliJ IDEA Ultimate Edition to a {prod-short} workspace
+
+{prod} supports connecting your local IntelliJ IDE to a running {prod-short} workspace over JetBrains Gateway.
+
+.Prerequisites
+
+. link:https://www.jetbrains.com/remote-development/gateway/[The JetBrains Gateway application] is installed.
+
+. link:https://plugins.jetbrains.com/plugin/24234-openshift-dev-spaces[The Gateway provider for OpenShift Dev Spaces] is installed.
+
+. In your local terminal, you are logged in to your OpenShift server with the OpenShift Client.
++
+[NOTE]
+====
+The `oc login` command establishes the authenticated session and saves the connection information to the configuration file which is read by the Gateway provider for OpenShift Dev Spaces.
+====
+
+.Connecting JetBrains IntelliJ IDEA Ultimate Edition to a new workspace
+
+.Procedure
+
+. Create a workspace on the {prod-short} Dashboard and choose `IntelliJ IDEA Ultimate (desktop)` editor:
++
+image::editor-idea-iu.png[IntelliJ IDEA Ultimate on Dashboard,link="{imagesdir}/editor-idea-iu.png"]
+
+. Wait for the prompt to open your local JetBrains Gateway application to appear:
++
+image::open-gateway-prompt.png[Open Gateway prompt,link="{imagesdir}/open-gateway-prompt.png"]
+
+Click the `Open Gateway` button to start your local JetBrains Client application connected to your Dev Spaces workspace:
+
+image::gateway-connecting.png[Connecting to remote host,link="{imagesdir}/gateway-connecting.png"]
+
+.Connecting JetBrains IntelliJ IDEA Ultimate Edition to an existing workspace
+
+There are two options to connect the local IntelliJ IDE to an existing workspace:
+
+* from the Che Dashboard
+* from the Gateway application
+
+The simplest way to connect to an existing workspace is to start a workspace from the {prod-short} Dashboard and click the `Open Gateway` button.
+However, with the Gateway application, you can connect the IntelliJ IDE to your workspace without accessing the {prod-short} Dashboard.
+
+.Procedure
+
+. Open the Gateway app and click `Connect to Dev Spaces`:
++
+image::gateway.png[JetBrains Gateway main window,link="{imagesdir}/gateway.png"]
+
+. On the next page, provide the parameters to connect to the OpenShift API server and click the `Check Connection and Continue` button:
++
+image::gateway-connect.png[Connecting to OpenShift API server,link="{imagesdir}/gateway-connect.png"]
+
+. Choose your workspace and click the `Connect` button:
++
+image::gateway-select-ws.png[Connecting to OpenShift API server,link="{imagesdir}/gateway-select-ws.png"]
+
+.Verification
+
+. Your local Gateway application is running the JetBrains Client and connects to the workspace.
++
+
+image::gateway-connecting.png[Connecting to remote host,link="{imagesdir}/gateway-connecting.png"]