Add comments to default archetype

Documenting non-obvious parameters, addressing #70

archetypes/default.md

@@ -2,9 +2,13 @@
 title = '{{ replace .TranslationBaseName "-" " " | title }}'
 date = {{ .Date }}
 draft = true
-meta_img = "/images/image.jpg"
 tags = ["tags"]
 description = "Desc"
+
+# For twitter cards, see https://github.com/mtn/cocoa-eh-hugo-theme/wiki/Twitter-cards
+meta_img = "/images/image.jpg"
+
+# For hacker news and lobsters builtin links, see github.com/mtn/cocoa-eh-hugo-theme/wiki/Social-Links
 hacker_news_id = ""
 lobsters_id = ""
 +++