update docker compose file to version 3

docker-compose.yml

@@ -1,4 +1,4 @@
-version: '2'
+version: '3'
 services:
   web:
     build:
@@ -8,8 +8,7 @@ services:
       - '80:80'
     volumes:
       - '.:/usr/src/app'
-    volumes_from:
-      - gem_cache
+      - gem_cache:/usr/local/bundle
     env_file:
       - .env
     expose:
@@ -17,10 +16,6 @@ services:
     stdin_open: true
     tty: true
     command: bundle exec rails s -p 80 -b '0.0.0.0'
-    depends_on:
-      - gem_cache
-  gem_cache:
-    image: ruby:2.3.1
-    command: bin/true
 volumes:
-      - /usr/local/bundle
+  gem_cache:
+    driver: local