Update README.algorithms

Author: Suxiaocai

README.algorithms

@@ -1,5 +1,5 @@
 README for GSQL Algorithm Library
-1/21/2020
+2/6/2020
 
 The GSQL Graph Algorithm Library is a collection of high-performance GSQL queries,
 each of which implements a standard graph algorithm. Each algorithm is ready to be
@@ -77,6 +77,7 @@ List of GSQL Graph Algorithms
 -----------------------------
 as of Oct 3, 2019
 
+betweenness_cent                Betweenness Centrality
 closeness_cent                  Closeness Centrality
 conn_comp                       Connected Component Detection
 wcc_fast                        Connected Components (Fast)