Add a Dockerfile to build and run Squawk (#422)

Introduce a multi-stage Dockerfile for the Squawk project. 

The builder stage compiles the Rust application, while the final stage creates a lightweight container to run Squawk as a non-root user. This setup improves portability and simplifies deployment.

Refers to #290

Author: alphayax

Dockerfile

@@ -0,0 +1,58 @@
+# Builder stage
+FROM rust:1-slim-bookworm AS builder
+
+# Labels for the builder stage
+LABEL stage=builder
+
+# Install build dependencies
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    libclang-dev \
+    perl \
+    pkg-config \
+    make \
+    && rm -rf /var/lib/apt/lists/*
+
+# Create a new empty shell project
+WORKDIR /usr/src/squawk
+
+# First, copy only the workspace configuration and toolchain files
+COPY Cargo.toml Cargo.lock rust-toolchain.toml ./
+
+# Copy the entire project
+COPY . .
+
+# Build the release version
+RUN cargo build --release
+
+# Final stage
+FROM debian:bookworm-slim
+
+# Metadata labels
+LABEL org.opencontainers.image.title="Squawk"
+LABEL org.opencontainers.image.description="Linter for PostgreSQL focused on database migrations"
+LABEL org.opencontainers.image.licenses="GPL-3.0"
+LABEL org.opencontainers.image.source="https://github.com/sbdchd/squawk"
+
+# Create a non-root user to run the application
+RUN groupadd -r squawk && useradd -r -g squawk squawk
+
+# Install runtime dependencies
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ca-certificates \
+    libssl-dev \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy the binary from the builder stage
+COPY --from=builder /usr/src/squawk/target/release/squawk /usr/local/bin/squawk
+
+# Set the ownership of the binary
+RUN chown squawk:squawk /usr/local/bin/squawk
+
+# Switch to non-root user
+USER squawk
+
+WORKDIR /data
+
+# Command to run when the container starts
+ENTRYPOINT ["squawk"]
+CMD ["--help"]