FEATURE: add child theme components in theme metadata.

Now theme creators can add an array of child theme components in about.json file for a top level theme.

app/models/remote_theme.rb

@@ -40,6 +40,7 @@ class RemoteTheme < ActiveRecord::Base
     theme ||= Theme.new(user_id: user&.id || -1, name: theme_info["name"])
 
     theme.component = theme_info["component"].to_s == "true"
+    theme.child_components = theme_info["components"].presence || []
 
     remote_theme = new
     remote_theme.theme = theme
@@ -63,6 +64,7 @@ class RemoteTheme < ActiveRecord::Base
     theme_info = RemoteTheme.extract_theme_info(importer)
     component = [true, "true"].include?(theme_info["component"])
     theme = Theme.new(user_id: user&.id || -1, name: theme_info["name"], component: component)
+    theme.child_components = theme_info["components"].presence || []
 
     remote_theme = new
     theme.remote_theme = remote_theme

app/models/theme.rb

@@ -2,6 +2,8 @@
 
 class Theme < ActiveRecord::Base
 
+  attr_accessor :child_components
+
   @cache = DistributedCache.new('theme')
 
   belongs_to :user
@@ -61,6 +63,17 @@ class Theme < ActiveRecord::Base
     notify_theme_change(with_scheme: notify_with_scheme)
   end
 
+  after_create do
+    if !component? && child_components.present?
+      child_components.each do |url|
+        url = ThemeStore::GitImporter.new(url.strip).url
+        theme = RemoteTheme.find_by(remote_url: url)&.theme
+        theme ||= RemoteTheme.import_theme(url, user)
+        child_themes << theme
+      end
+    end
+  end
+
   def update_javascript_cache!
     all_extra_js = theme_fields.where(target_id: Theme.targets[:extra_js]).pluck(:value_baked).join("\n")
     if all_extra_js.present?