install tzdata because of dependency in go program

Dockerfile

@@ -5,6 +5,7 @@ COPY . .
 RUN go build 
 FROM alpine
 WORKDIR /build
+RUN apk add --no-cache tzdata
 COPY --from=builder /build/wo-bisch-web /build/wo-bisch-web
 COPY snippets snippets
 COPY templates templates