Updated Dockerfile base image and fixed runtime permissions

Dockerfile

@@ -1,11 +1,21 @@
-FROM haskell:9.2.8-slim-buster
+FROM haskell:9.4.8-slim-buster
+
+ARG UID=1000
+ARG GID=1000
+
+RUN groupadd -g ${GID} saundersp \
+	&& useradd -l -m -u "${UID}" -g "${GID}" saundersp
+
+USER saundersp
 
 WORKDIR /home/saundersp/haskell_playground
 
 RUN cabal update
 
-COPY . .
+COPY app app
+COPY haskell-playground.cabal .
 
 RUN cabal build
 
-ENTRYPOINT ["cabal", "run"]
+ENTRYPOINT ["cabal"]
+CMD ["run"]