[build] license and READMEs

CONTRIBUTING.md

@@ -1,17 +1,45 @@
-# Contributing to RocksDB
+# Contributing to ForSt
 
 ## Code of Conduct
 The code of conduct is described in [`CODE_OF_CONDUCT.md`](CODE_OF_CONDUCT.md)
 
-## Contributor License Agreement ("CLA")
+## Basic Development Workflow
+As most open-source projects in github, ForSt contributors work on their forks, and send pull requests to ForSt’s repo. After a reviewer approves the pull request and all the CI check are passed, a ForSt team member will merge it.
 
-In order to accept your pull request, we need you to submit a CLA. You
-only need to do this once, so if you've done this for another Facebook
-open source project, you're good to go. If you are submitting a pull
-request for the first time, just let us know that you have completed
-the CLA and we can cross-check with your GitHub username.
+## Code style
+ForSt follows the RocksDB's code format.
+RocksDB follows Google C++ Style: https://google.github.io/styleguide/cppguide.html
+Note: a common pattern in existing RocksDB code is using non-nullable Type* for output parameters, in the old Google C++ Style, but this guideline has changed. The new guideline prefers (non-const) references for output parameters.
+For formatting, we limit each line to 80 characters. Most formatting can be done automatically by running
+```
+build_tools/format-diff.sh
+```
+or simply ```make format``` if you use GNU make. If you lack of dependencies to run it, the script will print out instructions for you to install them.
 
-Complete your CLA here: <https://code.facebook.com/cla>
 
-If you prefer to sign a paper copy, we can send you a PDF.  Send us an 
-e-mail or create a new github issue to request the CLA in PDF format.
+## License Claim
+ForSt is licensed under Apache 2.0 License. But since the RocksDB has its own license, we keep the license claim on top of each existing files, and use/add Apache 2.0 License on top of each new created files.
+```
+/* Copyright 2024-present, the ForSt authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+```
+
+## Submit patches
+Before you submit a patch, we strongly recommend that you share your ideas with others
+in the community via [Issues](https://github.com/ververica/ForSt/issues) or 
+[Discussions](https://github.com/ververica/ForSt/discussions). Of course, you do not
+need to do this if you are submitting a patch that can already be associated with an 
+issue, or a minor patch like a typo fix. You can then submit your patch via 
+[Pull Requests](https://github.com/ververica/ForSt/pulls), which requires a GitHub account.