Add dockerfile to run on railway

Author: paulocsanz

Dockerfile

@@ -0,0 +1,9 @@
+FROM rust:1.70.0-slim-bullseye
+
+WORKDIR /app
+
+COPY . .
+RUN cargo build --locked --release
+RUN cp ./target/release/server /bin/server
+
+CMD ["/bin/server"]