finalize persistence ofapp download metrics

src/Lib/Semver.hs

@@ -43,6 +43,4 @@ instance HasAppVersion AppVersion where
 
 appVersionMax :: HasAppVersion a => [a] -> Maybe a
 appVersionMax [] = Nothing
-appVersionMax as = Just $ maximumBy (\a1 a2 -> version a1 `compare` version a2) as
-
-
+appVersionMax as = Just $ maximumBy (\a1 a2 -> version a1 `compare` version a2) as

src/Lib/Types/Semver.hs

@@ -1,5 +1,7 @@
 {-# LANGUAGE QuasiQuotes     #-}
 {-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE TypeApplications #-}
+
 module Lib.Types.Semver where
 
 import           Startlude               hiding (break)
@@ -13,6 +15,7 @@ import           Data.Char               (isDigit)
 import           Data.String.Interpolate
 import           Data.Text
 import           Yesod.Core
+import           Database.Persist.Sql
 
 ------------------------------------------------------------------------------------------------------------------------
 -- Semver AppVersion
@@ -58,6 +61,13 @@ instance FromJSONKey AppVersion where
         Nothing -> fail "invalid app version"
         Just x -> pure x
 
+instance PersistField AppVersion where
+    toPersistValue = toPersistValue @String . show
+    fromPersistValue = note "" . readMaybe <=< fromPersistValue
+
+instance PersistFieldSql AppVersion where
+    sqlType _ = SqlString
+
 ------------------------------------------------------------------------------------------------------------------------
 -- Semver AppVersionSpecification
 ------------------------------------------------------------------------------------------------------------------------