add metadata field to channels

app/assets/stylesheets/custom.css.erb

@@ -51,6 +51,7 @@ body                    { padding-top: 70px; }
 .format-json,
 .format-xml             { display: none; }
 .format-block           { min-height: 200px; }
+.format-block-sm        { min-height: 50px; }
 .format-block-lg        { min-height: 350px; }
 .format-block-xl        { min-height: 400px; }
 .format-block-xxl       { min-height: 600px; }