Add a slug file fpco/stackage-server#37

Stackage/InstallInfo.hs

@@ -126,6 +126,14 @@ getInstallInfo settings = do
             , show now
             ]
 
+        System.IO.UTF8.writeFile (incexc </> "slug") $ concat
+            [ date
+            , "-"
+            , ghcVer
+            , if requireHaskellPlatform settings then "hp" else ""
+            , if isInc then "-inc" else "-exc"
+            ]
+
     return ii
 
 biToSPI :: BuildInfo -> SelectedPackageInfo

Stackage/ServerFiles.hs

@@ -37,7 +37,7 @@ createHackageFile isInc hp ii ghcVer date hackageH tarballH = do
     hPutStr tarballH $ concat
         [ "#!/bin/bash -ex\n\ntar czfv "
         , stackageFP
-        , " hackage desc ../build*"
+        , " hackage desc slug ../build*"
         ]
     indextargz <- getTarballName
     indexLBS <- L.readFile indextargz