Update dex build to use binary from arch instead of build from source

dex-images/tetris/Dockerfile

@@ -1,25 +1,21 @@
-FROM haskell:8
+FROM base/archlinux
 
-ENV DEXBUILD_DIR="/build"
+ENV DEXBUILD_DIR="/bin"
 
 RUN mkdir -p "${DEXBUILD_DIR}"
 
 WORKDIR ${DEXBUILD_DIR}
 
 RUN ( \
-  git clone "https://github.com/samtay/tetris.git" && \
-  cd tetris && \
-  git checkout tags/0.1.0 && \
-  rm -rf .git && \
-  mkdir bin && \
-  stack install --local-bin-path bin && \
+  curl -L https://github.com/samtay/tetris/releases/download/0.1.0/tetris-`uname -s`-`uname -m` -o tetris && \
+  chmod +x tetris && \
   true )
 
 #
 # container runtime configuration
 #
 
-ENTRYPOINT ["/build/tetris/bin/tetris"]
+ENTRYPOINT ["/bin/tetris"]
 
 #
 # v1 dex-api