[Findit] Re-org code.

appengine/findit/predator/README.md

Index: appengine/findit/predator/README.md
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+# Code structure
+
+* [analysis](analysis): Core library for analyzing Chrome crashes.
+* [app](app): The App Engine app to provide web APIs to analyze Chrome crashes through invoking the core library above, and web pages to view & monitor analysis results.
+
+# Refactoring guideline
+* All core logic of analysis should live in [analysis](analysis), and it should
+  be standalone, and not depend any App Engine APIs.
+* All app-layer code should live in [app](app)
+  * Frontend code rendering UIs to providing APIs for clients like ClusterFuzz/Fracas/Cracas should live in [app/frontend](app/frontend).
+  * Backend code running the analysis should live in [app/backend](app/backend).
+  * Shared code between the frontend and backend should live in [app/common](app/common).
+
+# Next step
+  When the refactoring is done, we will do a one-off move to appengine/predator.