Added compatibility warning for templates created using .fromDockerfile (#9)

Co-authored-by: Jakub Dobry <jakub.dobry8@gmail.com>

Author: mishushakov

template/migration.mdx

@@ -79,6 +79,14 @@ template = (
 
 </CodeGroup>
 
+<Info>
+    Only a limited set of instructions are supported and converted to equivalent template.
+
+    Compatible instructions:
+
+    `FROM`, `RUN`, `COPY`, `ADD`, `WORKDIR`, `USER`, `ENV`, `ARG`, `CMD`, `ENTRYPOINT`
+</Info>
+
 After the template definition, you can create the build scripts as described in the [Quickstart](/template/quickstart#create-a-development-build-script) section.