Add default value to the 'latest_deployed_at' field (#362)

* Add default value to the 'latest_deployed_at
 field

* Replace the method

Author: Noah Lee

Diff for: model/ent/entc.go

@@ -1,4 +1,4 @@
-// +build ignore
+//go:build ignore
 
 package main
 

Diff for: model/ent/repo/repo.go

@@ -34,6 +34,7 @@ func (Repo) Fields() []ent.Field {
 			UpdateDefault(nowUTC),
 		// Denormalization to sort with deployment.
 		field.Time("latest_deployed_at").
+			Default(zeroTime).
 			Optional(),
 		// The 'owner_id' field is the ID who activated the repository.
 		field.Int64("owner_id").

Diff for: model/ent/repo_create.go

@@ -19,3 +19,7 @@ func generateHash() string {
 func nowUTC() time.Time {
 	return time.Now().UTC()
 }
+
+func zeroTime() time.Time {
+	return time.Time{}
+}