Can edit settings on the embedding page

app/models/embedding.rb

@@ -0,0 +1,41 @@
+require 'has_errors'
+
+class Embedding < OpenStruct
+  include HasErrors
+
+  def self.settings
+    %i(embed_by_username
+       embed_post_limit
+       embed_truncate
+       embed_whitelist_selector
+       embed_blacklist_selector
+       feed_polling_enabled
+       feed_polling_url
+       embed_username_key_from_feed)
+  end
+
+  def base_url
+    Discourse.base_url
+  end
+
+  def save
+    Embedding.settings.each do |s|
+      SiteSetting.send("#{s}=", send(s))
+    end
+    true
+  rescue Discourse::InvalidParameters => p
+    errors.add :base, p.to_s
+    false
+  end
+
+  def embeddable_hosts
+    EmbeddableHost.all.order(:host)
+  end
+
+  def self.find
+    embedding_args = { id: 'default' }
+
+    Embedding.settings.each {|s| embedding_args[s] = SiteSetting.send(s) }
+    Embedding.new(embedding_args)
+  end
+end