Drop vestigial FileSystem effect requirement

src/Core.hs

@@ -11,9 +11,7 @@ import Database.PostgreSQL.Simple.FromRow   (FromRow, field, fromRow)
 import Database.PostgreSQL.Simple.ToField   (ToField, toField)
 import Database.PostgreSQL.Simple.ToRow     (ToRow, toRow)
 import Effectful
-import Effectful.Dispatch.Dynamic
 import Effectful.Error.Static               (Error, throwError)
-import Effectful.FileSystem                 (FileSystem)
 import Effectful.Reader.Static              (Reader)
 import GHC.Generics                         (Generic)
 import Servant hiding                       ((:>), throwError)
@@ -21,8 +19,7 @@ import Servant hiding                       ((:>), throwError)
 --
 -- Core data types
 --
-type AppEff = Eff '[ FileSystem
-                   , Logger
+type AppEff = Eff '[ Logger
                    , Database
                    , Reader AppEnv
                    , Error ServerError
@@ -51,6 +48,8 @@ instance ToJSON User
 instance FromJSON User
 
 data Database :: Effect where
+  DatabaseInit
+    :: Database (Eff es) ()
   DatabaseRead
     :: (ToField a, Show a, FromRow b) => (Query, a) -> Database (Eff es) [b]
   DatabaseRead_