feat: organisation logo (attachOne logo) and payload helpers

- Organisation gains the public attachOne logo (OrganisationLogoField),
  editable as an image upload on the Organisations form; avatar unchanged
- OrganisationLogoURL and OrganisationLogoFields give applications the
  has_logo, logo and logo_url keys for their organisation payloads
- no migration: attachments live in system_files

models/admin_models_test.go

@@ -53,9 +53,9 @@ func TestAdminModelContracts(t *testing.T) {
 	if (User{}).MorphName() != `Golem15\User\Models\User` || (Organisation{}).MorphName() != `Golem15\User\Models\Organisation` {
 		t.Fatalf("morph names = %q / %q", (User{}).MorphName(), (Organisation{}).MorphName())
 	}
-	for name, relations := range map[string]int{"user": len((User{}).AttachRelations()), "organisation": len((Organisation{}).AttachRelations())} {
-		if relations != 1 {
-			t.Fatalf("%s attach relations = %d", name, relations)
+	for name, want := range map[string][2]int{"user": {len((User{}).AttachRelations()), 1}, "organisation": {len((Organisation{}).AttachRelations()), 2}} {
+		if want[0] != want[1] {
+			t.Fatalf("%s attach relations = %d, want %d", name, want[0], want[1])
 		}
 	}
 	if rel := (User{}).AttachRelations()[0]; AvatarField != "avatar" || rel.Name != AvatarField || !rel.Public {
@@ -64,6 +64,9 @@ func TestAdminModelContracts(t *testing.T) {
 	if rel := (Organisation{}).AttachRelations()[0]; rel.Name != OrganisationAvatarField || !rel.Public {
 		t.Fatalf("organisation avatar relation = %+v", rel)
 	}
+	if rel := (Organisation{}).AttachRelations()[1]; OrganisationLogoField != "logo" || rel.Name != OrganisationLogoField || !rel.Public {
+		t.Fatalf("organisation logo relation = %+v", rel)
+	}
 
 	if got := (User{}).FilterScopes(); !reflect.DeepEqual(got, []string{FilterByGroup}) || FilterByGroup != "filterByGroup" {
 		t.Fatalf("User.FilterScopes = %v", got)

models/organisation.go

@@ -34,9 +34,15 @@ func (Organisation) MorphName() string { return `Golem15\User\Models\Organisatio
 // organisation's picture.
 const OrganisationAvatarField = "avatar"
 
-// AttachRelations declares the public attachOne avatar (PHP $attachOne).
+// OrganisationLogoField is the attachOne relation name of the
+// organisation's logo, the image a site shows wherever it displays the
+// organisation.
+const OrganisationLogoField = "logo"
+
+// AttachRelations declares the public attachOne avatar (PHP $attachOne) and
+// the public attachOne logo.
 func (Organisation) AttachRelations() []attach.Relation {
-	return []attach.Relation{{Name: OrganisationAvatarField, Public: true}}
+	return []attach.Relation{{Name: OrganisationAvatarField, Public: true}, {Name: OrganisationLogoField, Public: true}}
 }
 
 // Fillable is the PHP $fillable list.

models/organisation/fields.yaml

@@ -22,6 +22,13 @@ fields:
         mode: image
         imageWidth: 120
         imageHeight: 120
+    logo:
+        label: golem15.user::lang.organisation.logo
+        comment: golem15.user::lang.organisation.logo_comment
+        type: fileupload
+        mode: image
+        imageWidth: 240
+        imageHeight: 120
     members:
         type: relation-manager
         relation: members