Update README.md

Author: danolivo

README.md

@@ -24,7 +24,7 @@ installed with `make install`.
 
 ```
 cd postgresql-9.6                                                # enter postgresql source directory
-git clone https://github.com/tigvarts/aqo.git contrib/aqo        # clone aqo into contrib
+git clone https://github.com/postgrespro/aqo.git contrib/aqo        # clone aqo into contrib
 patch -p1 --no-backup-if-mismatch < contrib/aqo/aqo_pg<version>.patch  # patch postgresql
 make clean && make && make install                               # recompile postgresql
 cd contrib/aqo                                                   # enter aqo directory