To add your themes to the new "Layers Showcase" you need to issue a pull request and add a field to the top of showcase_json file. below is a template of the info you need to add.
Use the link below for the form. http://wh0cares.github.io
icons = H=256 x W=256 screenshots = H=1920. promo_header = W=1598 x H=1052
{
"title": "ELEMENT - Layers Theme",
"description": "Element, a new way of thinking theming. Created by users for users",
"author": "SPAstef",
"link": "https://play.google.com/store/apps/details?id=bitsykolayers.ELEMENT",
"icon": "http://i.imgur.com/fcBy21T.png",
"promo": "http://i.imgur.com/UIPe5pT.png",
"screenshot_1": "http://i.imgur.com/oJYrMXb.png",
"screenshot_2": "http://i.imgur.com/GNcwss5.png",
"screenshot_3": "http://i.imgur.com/gKjNJh3.png",
"googleplus": "https://plus.google.com/+StefanoTrevisani/posts/NGVQcadWxQp",
"version": "3.2.1",
"donate_link": "false",
"donate_version": "false",
"bootani": "false",
"font": "false",
"wallpaper": "http://i.imgur.com/KYOD5PA.png",
"plugin_version": "1",
"for_L": "true",
"for_M": "true",
"basic": "true",
"basic_m": "true",
"type2": "true",
"type3": "false",
"type3_m": "false",
"touchwiz": "true",
"lg": "true",
"sense": "true",
"xperia": "true",
"hdpi": "false",
"mdpi": "false",
"xhdpi": "true",
"xxhdpi": "true",
"xxxhdpi": "true",
"free": "false",
"donate": "false",
"paid": "true",
"needs_update": "false",
"will_update": "false"
}