Change to select reviewers into static reviewers (#201)

* Add Review entity.

* Add APIs for review.

* Replace approval into the review.

* Remove approval entity.

Author: Noah Hanjun Lee

deploy.yml

@@ -22,6 +22,8 @@ envs:
       - "react-test"
       - "publish-image"
     production_environment: true
-    approval:
+    review:
       enabled: true
-      required_count: 0
+      reviewers: 
+        - hanjunlee
+        - noah-qa