feat: Enable Docker deployment and CD

Closes #8, partially addresses #6

Dockerfile

@@ -0,0 +1,46 @@
+ARG RUST_VERSION=1.73.0
+FROM rust:${RUST_VERSION}-slim-bullseye AS build
+
+RUN --mount=type=cache,target=/usr/local/cargo/registry \
+    cargo install sqlx-cli --no-default-features --features rustls,sqlite && \
+    cp /usr/local/cargo/bin/sqlx /bin/sqlx
+
+ENV DATABASE_URL=sqlite:/var/p4bl0t.db
+
+WORKDIR /app
+RUN --mount=type=bind,source=src,target=src \
+    --mount=type=bind,source=Cargo.toml,target=Cargo.toml \
+    --mount=type=bind,source=Cargo.lock,target=Cargo.lock \
+    --mount=type=bind,source=migrations,target=migrations \
+    --mount=type=cache,target=/app/target/ \
+    --mount=type=cache,target=/usr/local/cargo/registry \
+    <<EOF
+set -e
+sqlx database create
+sqlx migrate run
+cargo build --locked --release
+cargo install --path .
+EOF
+
+
+FROM debian:bullseye-slim AS final
+
+RUN apt-get update && apt-get install -qqy ca-certificates
+ARG UID=10001
+RUN adduser \
+    --disabled-password \
+    --gecos "" \
+    --home "/nonexistent" \
+    --shell "/sbin/nologin" \
+    --no-create-home \
+    --uid "${UID}" \
+    appuser
+USER appuser
+
+ENV DATABASE_URL=sqlite:/var/p4bl0t.db
+ENV DISCORD_TOKEN=changeme
+
+COPY --from=build /usr/local/cargo/bin/p4bl0t /bin
+COPY --chown=appuser --from=build /var/p4bl0t.db /var/p4bl0t.db
+
+CMD [ "p4bl0t" ]