Refactor to FileService and PostgresService

src/main/scala/app/Main.scala

@@ -2,15 +2,15 @@ package app
 
 import cats.effect._
 import cats.implicits.catsSyntaxTuple2Parallel
-import db.{DBService, DataService}
+import db.{FileService, DataService}
 import fetch.{FetchService, FileFetchScheduler}
 import server.Server
 
 object Main extends IOApp {
   def run(args: List[String]): IO[ExitCode] = {
     for {
-      dbService <- DBService.of
-      dataService <- DataService.of(dbService)
+      fileService <- FileService.of
+      dataService <- DataService.of(fileService)
 
       fetch <- FetchService.of
       fileFetchScheduler <- FileFetchScheduler.of(dataService, fetch)