adding apt-get update

Author: Florian Treml

frontend/Dockerfile

@@ -1,7 +1,7 @@
 FROM ubuntu:18.04
 
 RUN apt-get update && apt-get -y install curl gnupg && curl -sL https://deb.nodesource.com/setup_14.x  | bash - && apt-get -y install nodejs
-RUN apt-get install -y dos2unix sox libsox-fmt-mp3 libttspico-utils ffmpeg
+RUN apt-get update && apt-get install -y dos2unix sox libsox-fmt-mp3 libttspico-utils ffmpeg
 
 WORKDIR /app
 COPY ./package.json /app/package.json