readd WORKDIR /app

`config.toml` uses relative path, from the current directory, `$PWD` by default is `/`.

commit f337f6c
removed `WORKDIR /app`, and `/config.toml` was used instead of `/app/config.toml`.
The change was breaking, unexpected and undocumented.
As users already mount `/app/config.toml`, revert to using it.

Revert 16315c0
(what was workaround for breaking change,
though there is no need to break anything here)

Closes mxpv#270

Dockerfile

@@ -7,5 +7,7 @@ RUN wget -O /usr/bin/youtube-dl https://github.com/ytdl-org/youtube-dl/releases/
     apk --no-cache add ca-certificates python ffmpeg tzdata
 COPY podsync /podsync
 
+# (/app/)config.toml is relative, depends on /app working directory
+WORKDIR /app
 ENTRYPOINT ["/podsync"]
 CMD ["--no-banner"]

docker-compose.yml

@@ -9,4 +9,4 @@ services:
       - 80:80
     volumes:
       - ./data:/data/
-      - ./config.toml:/config.toml
+      - ./config.toml:/app/config.toml