Include package count on snapshot page

Handler/StackageHome.hs

@@ -21,6 +21,7 @@ getStackageHomeR name = do
             let queryText = "" :: Text
                 exact = False
             in $(widgetFile "hoogle-form")
+    packageCount <- getPackageCount sid
     defaultLayout $ do
         setTitle $ toHtml $ snapshotTitle snapshot
         packages <- getPackages sid

Stackage/Database.hs

@@ -37,6 +37,7 @@ module Stackage.Database
     , currentSchema
     , last5Lts5Nightly
     , snapshotsJSON
+    , getPackageCount
     ) where
 
 import Database.Sqlite (SqliteException)
@@ -735,3 +736,8 @@ snapshotsJSON = do
         "lts-" ++ show major ++ "." ++ show minor
 
     printNightly day = "nightly-" ++ tshow day
+
+getPackageCount :: GetStackageDatabase m
+                => SnapshotId
+                -> m Int
+getPackageCount sid = run $ count [SnapshotPackageSnapshot ==. sid]

templates/stackage-home.hamlet

@@ -38,7 +38,7 @@ $newline never
     <a href=@{SnapshotR name HoogleDatabaseR}>
       Download this hoogle database
 
-    <h3>Packages
+    <h3>Packages (#{packageCount})
 
     <p>
         <a href=@{SnapshotR name DocsR}>View documentation by modules