add cabal update to install steps

README.md

@@ -11,6 +11,8 @@
 
 ## Installing the latest development version from github
 
+    cabal update
+
     REPOS="hamlet persistent wai yesod"
     for repo in $REPOS
     do

install-all.sh

@@ -8,7 +8,7 @@ do
     echo Installing $package
     cd $package
     ($CABAL configure --enable-tests ||
-      ($CABAL install --only-dependencies && $CABAL configure --enable-tests)
+      ($CABAL update && $CABAL install --only-dependencies && $CABAL configure --enable-tests)
     ) && $CABAL build && $CABAL test && ./Setup.lhs install || exit
     cd ..
 done