update docker-compose with persistent dir for grocery app cache

.gitmodules

@@ -1,13 +1,9 @@
 [submodule "prayer-generator"]
 	path = prayer-generator
 	url = https://gogs.shandan.one/gogsadmin/prayer-generator.git
-	branch = templates
+	branch = master
 
 [submodule "grocery-transactions"]
 	path = grocery-transactions
-	#url = /home/pi/git/grocery_transactions.git
 	url = https://gogs.shandan.one/gogsadmin/grocery-manager.git
-	#branch = master
 	branch = vertical-button-groups
-	#branch = filter-tables
-	#branch = limit-url-length

docker-compose.yml

@@ -40,6 +40,8 @@ services:
       HOST: 192.168.0.20
       USER: pi
       PASSWORD: ${GROCERYDB_PASSWORD}
+    volumes:
+      - ./grocery-files:/usr/src/app/app/rest/static/files
     expose:
       - 6772
     networks: