Link to secure integration doc

Add a link to the Security scanner integration doc.

doc/user/application_security/container_scanning/index.md

@@ -25,6 +25,10 @@ merge request.
 
 ![Container Scanning Widget](img/container_scanning_v12_9.png)
 
+## Contribute your scanner
+
+The [Security Scanner Integration](../../../development/integrations/secure.md) documentation explains how to integrate other security scanners into GitLab.
+
 ## Use cases
 
 If you distribute your application with Docker, then there's a great chance

doc/user/application_security/dependency_scanning/index.md

@@ -67,6 +67,10 @@ The following languages and dependency managers are supported.
 | Scala ([sbt](https://www.scala-sbt.org/)) | yes | [gemnasium](https://gitlab.com/gitlab-org/security-products/gemnasium) |
 | Go ([Go Modules](https://github.com/golang/go/wiki/Modules)) | yes ([alpha](https://gitlab.com/gitlab-org/gitlab/issues/7132)) | [gemnasium](https://gitlab.com/gitlab-org/security-products/gemnasium) |
 
+## Contribute your scanner
+
+The [Security Scanner Integration](../../../development/integrations/secure.md) documentation explains how to integrate other security scanners into GitLab.
+
 ## Configuration
 
 For GitLab 11.9 and later, to enable Dependency Scanning, you must

doc/user/application_security/sast/index.md

@@ -89,6 +89,10 @@ The Java analyzers can also be used for variants like the
 [Gradle wrapper](https://docs.gradle.org/current/userguide/gradle_wrapper.html),
 [Grails](https://grails.org/) and the [Maven wrapper](https://github.com/takari/maven-wrapper).
 
+## Contribute your scanner
+
+The [Security Scanner Integration](../../../development/integrations/secure.md) documentation explains how to integrate other security scanners into GitLab.
+
 ## Configuration
 
 For GitLab 11.9 and later, to enable SAST, you must