fix file permission issues in 'dev' docker setup

deploy/dev/docker-compose.yml

@@ -6,11 +6,12 @@ services:
     command: bash -c 'python manage.py migrate && python testdata.py && python manage.py runserver 0.0.0.0:8000'
     environment:
       - HTTP_HOST=core
-      - DB_FILE=dev.db
+      - DB_FILE=dev.sqlite3
       - DEBUG_MODE_ACTIVE=true
     volumes:
-      - ../../core:/code
-      - ../testdata.py:/code/testdata.py
+      - ../../core:/code:ro
+      - ../testdata.py:/code/testdata.py:ro
+      - backend_testcontext:/code
     ports:
       - "8000:8000"
 
@@ -21,9 +22,13 @@ services:
     command: npm run serve
     volumes:
       - ../../web:/web:ro
-      - /web/node_modules
-      - ./vue.config.js:/web/vue.config.js
+      - ./vue.config.js:/web/vue.config.js:ro
+      - frontend_testcontext:/web/node_modules
     ports:
       - "8080:8080"
     depends_on:
       - core
+
+volumes:
+  backend_testcontext:
+  frontend_testcontext: