Add self compatibility badge (#58)

Author: liyanhui1228

README.rst

@@ -23,6 +23,17 @@ Dependency Management Toolkit for Google Cloud Python Projects
 
 .. _Compatibility Status Dashboard: https://googlecloudplatform.github.io/cloud-opensource-python/
 
+-  Compatibility check results
+
+.. csv-table::
+   :header: "CHECK_TYPE", "RESULT"
+   :widths: 20, 30
+
+   "Self Compatibility", |self_compatibility|
+
+.. |self_compatibility| image:: http://35.226.8.89/self_compatibility_badge/image?package=compatibility_lib
+   :target: http://35.226.8.89/self_compatibility_badge/target?package=compatibility_lib
+
 License
 -------