Update README.md

Add release date and documentation descriptions of this project

README.md

@@ -1 +1,28 @@
-lab4
+# Cafe Online Retailing System
+
+This is the back end of a cafe online retailing system. The system is driven by SpringBoot with sufficient testing. Meanwhile, this is a course team project on the Software Engineering course at Software School, Fudan University. 
+
+## Releases
+
+There are Four release dates.
+
+The last commit before the data specified below are correponding releases.
+
+| Lab Name | Release Date   |
+|----------|----------------|
+| Lab 2    | March 20, 2019 |
+| Lab 3    | April 1, 2019  |
+| Lab 4    | April 28, 2019 |
+| Lab 5    | May 30, 2019   |
+| Lab 6    | Jun 23, 2019   |
+
+
+## Documentation
+
+For each release version of this project, there is a detailed documentation describing the featuers and fixes of this revision. The documentation is compiled by TeX and the TeX source code plus all the binary attachments are provided in the following repositories.
+
+For the documentation of Lab 2 and Lab 3, please refer to <https://github.com/StrayBird-ATSH/CafeOnlineRetailingSystem_Doc_Initial>;
+
+For the documentation of Lab 4-6, please refer to <https://github.com/StrayBird-ATSH/CafeOnlineRetailingSystem_Doc_Final>.
+
+All the documentation have the same release date as the project code. Therefore, the last commit bofore the date specified in the table above(including) can be used as the release version of the documentation of the specific release version.