feat: add change detection module

internal/feed/primitives.go

@@ -48,6 +48,14 @@ type AppRelease struct {
 
 type AppReleases []AppRelease
 
+type ChangeWatch struct {
+	Name        string
+	Url         string
+	LastChanged time.Time
+}
+
+type ChangeWatches []ChangeWatch
+
 type Video struct {
 	ThumbnailUrl string
 	Title        string
@@ -200,6 +208,14 @@ func (r AppReleases) SortByNewest() AppReleases {
 	return r
 }
 
+func (r ChangeWatches) SortByNewest() ChangeWatches {
+	sort.Slice(r, func(i, j int) bool {
+		return r[i].LastChanged.After(r[j].LastChanged)
+	})
+
+	return r
+}
+
 func (v Videos) SortByNewest() Videos {
 	sort.Slice(v, func(i, j int) bool {
 		return v[i].TimePosted.After(v[j].TimePosted)