updated README.md

README.md

@@ -6,9 +6,12 @@ CSST L1 pipeline prototype.
 ## homepage
 
 This code is available on *CSST GitLab*:
+- [https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto](https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto).
 
-[https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto](https://csst-tb.bao.ac.cn/code/csst-l1/csst_proto).
+## documentation
 
+A sphinx-based documentation is available at
+- [https://csst-proto.readthedocs.io/en/latest/](https://csst-proto.readthedocs.io/en/latest/)
 
 ## installation
 
@@ -65,3 +68,22 @@ The `csst_proto` uses an awesome algorithm based on `numpy.ndarray` indices to f
 | `requirements.txt` | code requirements               | √      | √   |     |
 | `setup.py`         | sphinx-based documentation      | √√     | √   |     |
 
+## important stages
+
+1. **installation**: `source code` & `setup.py` -> `pip install <package_name>`
+2. **a simple guide**: `README.md`
+3. **unittest**: `pytest`
+4. gitlab CI/CD pipeline: `.gitlab-ci.yml`
+5. sphinx-based documentation: `doc/` & `readthedocs.yml`
+
+## necessary skills
+
+- git: https://git-scm.com/
+  - Pro Git: https://git-scm.com/book/en/v2
+- Numpydoc: https://numpydoc.readthedocs.io/en/latest/format.html
+  - for C: https://peps.python.org/pep-0007/
+  - for Python: https://peps.python.org/pep-0008/
+- unittest: https://docs.python.org/3.8/library/unittest.html
+- sphinx: https://www.sphinx-doc.org/en/master/index.html
+- restructured text: https://docutils.sourceforge.io/rst.html
+- readthedoc: https://readthedocs.io/ or https://rtfd.io/
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