adjust docker image

Dockerfile

@@ -1,20 +1,16 @@
-FROM registry.gitlab.com/etke.cc/base AS builder
+FROM registry.gitlab.com/etke.cc/base/build AS builder
 
 WORKDIR /postmoogle
 COPY . .
 RUN make build
 
-FROM alpine:latest
+FROM registry.gitlab.com/etke.cc/base/app
 
 ENV POSTMOOGLE_DB_DSN /data/postmoogle.db
 
-RUN apk --no-cache add ca-certificates tzdata olm && \
-    adduser -D -g '' postmoogle && \
-    mkdir /data && chown -R postmoogle /data
-
 COPY --from=builder /postmoogle/postmoogle /bin/postmoogle
 
-USER postmoogle
+USER app
 
 ENTRYPOINT ["/bin/postmoogle"]