add submodule design-pattern

Author: twotwo

.gitmodules

@@ -7,3 +7,6 @@
 [submodule "loguru-sample"]
 	path = loguru-sample
 	url = https://github.com/twotwo/python-loguru-sample
+[submodule "design-pattern"]
+	path = design-pattern
+	url = https://github.com/twotwo/python-design-pattern

README.md

@@ -2,9 +2,11 @@
 
 ## Submodules
 
-- [pandas-sample](https://github.com/twotwo/python-pandas-sample)
 - [grpc-sample](https://github.com/twotwo/python-grpc-sample)
+- [loguru-sample](https://github.com/twotwo/python-loguru-sample)
+- [pandas-sample](https://github.com/twotwo/python-pandas-sample)
 
 ```bash
+git clone --recurse-submodules https://github.com/twotwo/python-libs # or
 git submodule update --init --recursive
 ```