Update Dockerfile

Dockerfile

@@ -6,6 +6,7 @@ WORKDIR /usr/src/app
 # A wildcard is used to ensure both package.json AND package-lock.json are copied
 # where available (npm@5+)
 COPY package*.json ./
+COPY src ./
 RUN yarn
 RUN yarn build
 # If you are building your code for production