Update install.sh to manage home correctly

ci/install.sh

 #!/bin/bash
 # Ce script est utilisé pour paramétrer l'environnement du site
-if [ -e "./app/env" ]
+if [ 'x$PROD_HOME' -ne 'x' ]
 then
-    source app/env
+    HOME=$PROD_HOME
+else
+    HOME=/var/www/dons/
+fi
+
+if [ -e "$HOME/app/env"]
+    then
+        source $HOME/app/env
+    fi
 fi    
 
-cd /home/don/don
+cd $HOME
 git reset --hard
 git pull origin $CI_BUILD_REF_NAME
 git checkout $CI_BUILD_REF_NAME
@@ -16,7 +24,7 @@ composer install --no-dev
 composer update
 
 # Let's run the migrations
-if [ -e "phinx.yml" ]
+if [ -e "$HOME/phinx.yml" ]
 then
     case $CI_BUILD_REF_NAME in
         master)