actually readme

README.md

@@ -1,4 +1,14 @@
 
 # reploy
 
-A redo of deployment of R3 sites.
+A redo of deployment of the R3 sites (cards for now).
+
+## How to use this
+
+- install haskell platform (e.g. with https://www.haskell.org/ghcup/)
+- `cabal run site -- --help` shows options
+- `cabal run site` builds a demo site
+- `cabal install` produces and installs an executable `site` into the cabal
+  path (you can use it as a program directly)
+
+