Merge pull request kubernetes-client#245 from mbohlool/doc

Add basic submodules documentation

devel/submodules.md

@@ -0,0 +1,27 @@
+# Submodules
+To comply with [client library structure requirement](https://github.com/kubernetes-client/community/blob/master/design-docs/clients-library-structure.md),
+python client base utilities is moved into kubernetes-client/python-base repo. `git submodules` is being used to handle dependency to that repo.
+This document will provide basic steps to get submodules work.
+
+# Clone repo
+To clone repo, you need to pass `recursive` parameter to make the clone also get submodules:
+
+```bash
+git clone --recursive https://github.com/kubernetes-incubator/client-python.git
+```
+
+if you already clone repo with no `--recursive` option, you can run this command to get submodules:
+
+```bash
+git submodule update --init
+```
+
+# Update submodule
+If you changed kubernetes-client/python-base and want to pull your changes into this repo run this command:
+
+```bash
+git submodule update --remote
+```
+
+Once updated, you should create a new PR to commit changes to the repository.
+