Cleaned up dockerfile, removing unused packages after build. Image reduced from ~350 MB to 75 MB.

Dockerfile

@@ -1,6 +1,9 @@
 # Can't use buster-slim because it needs librtlsdr-dev 0.5.3
 # See https://github.com/dgiardini/rtl-ais/issues/32
 FROM debian:stretch-slim
+LABEL "name"="rtl-ais" \
+  "description"="AIS ship decoding using an RTL-SDR dongle" \
+  "author"="Bryan Klofas KF6ZEO"
 
 ENV APP=/usr/src/app
 
@@ -9,17 +12,16 @@ WORKDIR $APP
 COPY . $APP
 
 RUN apt-get update && apt-get install -y \
-git \
-rtl-sdr \
-librtlsdr-dev \
-make \
-build-essential \
-pkg-config \
-libusb-1.0-0-dev \
-&& make \ 
-&& rm -rf /var/lib/apt/lists/*
+  rtl-sdr \
+  librtlsdr-dev \
+  libusb-1.0-0-dev \
+  make \
+  build-essential \
+  pkg-config \
+  && make \ 
+  && apt-get remove -y make build-essential pkg-config \
+  && apt-get autoremove -y \
+  && rm -rf /var/lib/apt/lists/*
 
 CMD $APP/rtl_ais -n
 
-#EXPOSE 10110/udp
-