update dockerfile: no longer build on run

Dockerfile

@@ -1,10 +1,10 @@
-FROM rust:1.81
+FROM rust:1.81 AS builder
 WORKDIR /usr/src/bot
 COPY . .
 
-# FROM ubuntu:24.10
-# COPY --from=builder /usr/local/cargo/bin/bot /usr/local/bin/bot
+RUN cargo --install --path .
 
-# temporary fix for slow cross compile builds.
-# this will simply compile and run the code on `docker run`
-CMD ["cargo", "run", "--release"]
+FROM ubuntu:24.10
+COPY --from=builder /usr/local/cargo/bin/bot /usr/local/bin/bot
+
+CMD ["bot"]