Create final Docker image using Alpine Linux to keep things smol

Dockerfile

@@ -1,9 +1,11 @@
-FROM golang:latest
-
+FROM golang:latest AS build
 WORKDIR /go/src/buttsbot
 COPY . .
-
 RUN go get -d -v ./...
 RUN go install -v ./...
 
-CMD ["buttsbot"]
+FROM alpine:latest
+run apk add --no-cache bash
+WORKDIR /app
+COPY --from=build /go/bin/buttsbot discord-buttsbot
+CMD ./discord-buttsbot