add functions description

README.md

@@ -3,6 +3,12 @@
 * This project provides a project structure for cuda project.
 * To build the project, just run `mkdir build && cd build && cmake .. && make `
 
+### Functions
+
+* (DONE) Matrix Multiplication
+* (DONE) Vector Multiplication
+* (TODO) try cuBLAS, cuDNN libs
+
 ### Created by
 
 Lv Zhengyang (吕政阳)