Adding docker image

Reviewed-on: #4
Co-authored-by: Igor Ranieri <igor@elland.me>
Co-committed-by: Igor Ranieri <igor@elland.me>

Dockerfile

@@ -0,0 +1,30 @@
+FROM haskell:9.10
+
+# Install system dependencies
+RUN apt-get update && apt-get install -y \
+    git \
+    curl \
+    && rm -rf /var/lib/apt/lists/*
+
+# Install Node.js (for GitHub Actions compatibility)
+RUN curl -fsSL https://deb.nodesource.com/setup_22.x | bash - && \
+    apt-get install -y nodejs && \
+    rm -rf /var/lib/apt/lists/*
+
+# Update cabal and install Haskell tools
+RUN cabal update && \
+    cabal install --install-method=copy --installdir=/usr/local/bin \
+    fourmolu \
+    hlint \
+    cabal-gild
+
+# Verify installations
+RUN ghc --version && \
+    cabal --version && \
+    node --version && \
+    fourmolu --version && \
+    hlint --version && \
+    cabal-gild --version
+
+# Set working directory
+WORKDIR /workspace