add comment to build_binary.sh

build_binary.sh

@@ -1,4 +1,10 @@
 MIX_ENV=prod BOOMBOX_BURRITO=true mix release --overwrite && \
 mv burrito_out/boombox_current boombox && \
 rm -r burrito_out && \
+# Burrito extracts the compressed artifacts into a common
+# location in the system on a first run, and then reuses
+# those artifacts and checks the version in mix.exs to
+# know whether it car reuse them. So we need to uninstall
+# the artifacts to force burrito to extract them again
+# even if the version in mix.exs didn't change
 yes | ./boombox maintenance uninstall