Add themes docs

_docs/plugins/themes.md

@@ -0,0 +1,49 @@
+---
+layout: documentation
+title: Themes
+category: Plugins
+order: 5.1
+---
+
+# Finding Themes
+
+Themes published on npm should have the keyword `lounge-theme`, so you can find a list by [searching on npmjs.org](https://www.npmjs.com/search?q=keywords%3Alounge-theme).
+
+# Installing Themes
+
+To install theme `lounge-theme-custom`
+
+* `npm install lounge-theme-custom`
+* Add `lounge-theme-custom` to the `plugins` array in `config.js`
+* Restart The Lounge
+* Select theme in options
+
+# Creating Themes
+
+Create an npm package using the base example.json below, and publish to npm.
+
+```
+{
+  "name": "lounge-theme-custom", // Replace 'custom' with your theme's name
+  "version": "1.0.0",
+  "description": "A theme for The Lounge",
+  "main": "package.json",
+  "lounge": {
+    "css": "theme.css", // Set to the theme css file
+    "type": "theme"
+  },
+  "license": "MIT",
+  "homepage": "https://github.com/username/lounge-theme-custom", // Set to your homepage
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/username/lounge-theme-custom.git" // Set your git repository
+  },
+  "keywords": [
+    "lounge",
+    "lounge-theme"
+  ],
+  "bugs": {
+    "url": "https://github.com/username/lounge-theme-custom/issues" // Set to a page for people to file issues
+  }
+}
+```