Broken Dockerfile for docker-101

docs_en/tutorial/our-application/index.md

@@ -53,7 +53,7 @@ see a few flaws in the Dockerfile below. But, don't worry! We'll go over them.
     ```dockerfile
     FROM node:10-alpine
     WORKDIR /app
-    COPY . .
+    COPY app .
     RUN yarn install --production
     CMD ["node", "/app/src/index.js"]
     ```