[WIP] Introduce repo creation on push (#273)

Introduce repo creation on push

_config.yml

@@ -56,9 +56,11 @@ dtr_versions:
 tablabels:
   ucp-3.0: Universal Control Plane 3.0
   ucp-2.2: Universal Control Plane 2.2
+  dtr-2.5: Docker Trusted Registry 2.5
   docker-cli-linux: Docker CLI on Mac/Linux
   docker-cli-win: Docker CLI on Windows
   kubectl: Kubernetes CLI
+  cli: CLI
 
 collections:
   samples:

deploy/allow-creation-on-push.md

@@ -0,0 +1,43 @@
+---
+title: Allow users to create repositories when pushing
+description: By default Docker Trusted Registry only allows pushing images to
+  existing repositories. Learn how to change that.
+keywords: dtr, repository
+ui_tabs:
+- version: dtr-2.5
+  orhigher: true
+cli_tabs:
+- version: cli
+---
+
+{% if include.ui %}
+{% if include.version=="dtr-2.5" %}
+By default DTR only allows pushing images if the repository exists, and you
+have write access to the repository.
+
+As an example, if you try to push to `dtr.example.org/library/java:9`, and the
+`library/java` repository doesn't exist yet, your push fails.
+
+You can configure DTR to allow pushing to repositories that don't exist yet.
+As an administrator, log into the **DTR web UI**, navigate to the **Settings**
+page, and enable **Create repository on push**.
+
+![DTR settings page](images/create-on-push-1.png){: .with-border}
+
+From now on, when a user pushes to their personal sandbox
+(`<user-name>/<repository>`), or if the user is an administrator for the
+organization (`<org>/<repository>`), DTR will create a repository if it doesn't
+exist yet. In that case, the repository is created as private.
+{% endif %}
+{% endif %}
+
+
+{% if include.cli %}
+```bash
+curl --user <admin-user>:<password> \
+--request POST "<dtr-url>/api/v0/meta/settings" \
+--header "accept: application/json" \
+--header "content-type: application/json" \
+--data "{ \"createRepositoryOnPush\": true}"
+```
+{% endif %}