Add ansible virtual repositories

docs/ansible/virtual.md

@@ -0,0 +1,28 @@
+# `ansible` virtual
+
+An ansible virtual serves one Galaxy v3 API over local and remote ansible
+members: `ansible-galaxy collection install` works against
+`/api/v1/virtual/<name>/`.
+
+- `versions/` concatenates member version lists in member order; on a
+  duplicate version the earlier member wins. Pagination (`limit` up to 100,
+  `offset`) runs over the merged list.
+- `versions/<version>/` is the owning member's detail with `href` and
+  `download_url` pointing at the virtual; the download 302s to that member.
+- A member error fails the request with 502; a member without the collection
+  is skipped. Merges are cached for 60s.
+
+```hcl
+resource "artifactapi_virtual" "ansible" {
+  name         = "ansible"
+  package_type = "ansible"
+  members      = [artifactapi_local_ansible.internal.name, artifactapi_remote_ansible.galaxy.name]
+}
+```
+
+```bash
+ansible-galaxy collection install unkin.hello community.general \
+  --server https://artifactapi.example.com/api/v1/virtual/ansible/
+```
+
+Publish to the local member directly; the virtual is read-only.