Add container registry info for gitea

pages/02.linux/gitea/default.en.md

@@ -103,3 +103,17 @@ List users:
 
 Change user password:  
 `$ gitea admin user change-password -u (user) -p (password)`
+
+## Package Management
+
+### Container Registry
+
+Gitea comes with a built-in container registry.
+
+#### Login
+
+`$ podman login gitea.exu.li`
+
+#### Push image
+
+`$ podman push <IMAGE ID> docker://gitea.exu.li/<OWNER>/<IMAGE>:<TAG>`