update

README.md

@@ -18,6 +18,13 @@ sudo apt-get install build-essential libx11-dev mesa-common-dev libgl1-mesa-dev
 
 ### Build
 
+Clone this repo (together with the submodule `libigl`):
+```
+git clone --recursive http://dalab.se.sjtu.edu.cn/gitlab/dalab/ca-framework-2020.git
+# if you forget clone submodule at first place
+git submodule update --init --recursive
+``` 
+
 Run the following commands inside the relevant subfolder to setup the build folder:
 ```
 mkdir build