Update Dockerfile to install libsnappy-dev and to use current source code

Also, update Docker usage documentation.

.dockerignore

@@ -0,0 +1,3 @@
+target/
+.git/
+_*/

Dockerfile

@@ -1,14 +1,17 @@
-FROM rust:latest
+FROM rust:1.33.0-slim
 
 RUN apt-get update
 RUN apt-get install -y clang cmake
-
-RUN cargo install electrs
+RUN apt-get install -y libsnappy-dev
 
 RUN adduser --disabled-login --system --shell /bin/false --uid 1000 user
 
 USER user
 WORKDIR /home/user
+COPY ./ /home/user
+
+RUN cargo build --release
+RUN cargo install --path .
 
 # Electrum RPC
 EXPOSE 50001
@@ -17,5 +20,3 @@ EXPOSE 50001
 EXPOSE 4224
 
 STOPSIGNAL SIGINT
-
-CMD ["electrs", "-vvvv", "--timestamp"]

doc/usage.md

@@ -122,9 +122,10 @@ $ electrum --oneserver --server=example:50002:s
 ```bash
 $ docker build -t electrs-app .
 $ docker run --network host \
-             --volume /home/roman/.bitcoin:/home/user/.bitcoin:ro \
+             --volume $HOME/.bitcoin:/home/user/.bitcoin:ro \
              --volume $PWD:/home/user \
-             --rm -i -t electrs-app
+             --rm -i -t electrs-app \
+             electrs -vvvv --timestamp --db-dir /home/user/db
 ```
 
 ## Monitoring