root file fix

Author: Gunasekar-K

docker/Dockerfile

@@ -8,6 +8,8 @@ COPY . /challenge-api
 WORKDIR /challenge-api
 
 # Install the dependencies from package.json
+RUN mkdir -p /yarncache
+ENV YARN_CACHE_FOLDER=/yarncache
 RUN yarn install
 
-CMD yarn start
+CMD yarn start