adding cd to the INSTALL

INSTALL.md

@@ -38,6 +38,7 @@ vim conf/Conf.php
 ```bash
 git clone https://gitlab.mbb.univ-montp2.fr/jlopez/wicopa.git
 # you need to have wicopa.sql here
+cd wicopa
 wget http://web.mbb.univ-montp2.fr/download/wicopa.sql.gz && gunzip -d wicopa.sql.gz
 
 sudo docker-compose up --build