add mention of `libraries` template variable for config template

config/config.yml.template

@@ -29,6 +29,8 @@ libraries:                       # This is called out once within the config.yml
       - file: config/Music.yml   # This is a local file THAT YOU MIGHT CREATE
 playlist_files:
   - pmm: playlist                # This is a file within PMM's defaults folder
+    template_variables:
+      libraries: Movies, TV Shows   # list of libraries that you want the PMM Defaults playlists to look at
   # see the wiki for how to use local files, folders, URLs, or files from git
 settings:
   cache: true

docs/defaults/playlist.md

@@ -4,6 +4,7 @@ The `playlist` Default Metadata File is used to create playlists based on popula
 
 This Default file requires [Trakt Authentication](../config/trakt)
 
+This file assumes that you have libraries named `Movies` and `TV Shows`. If you do not have these libraries or want to use alternative/additional libraries, use the `libraries` template variable which is outlined in the [Template Variables](#template-variables) table.
 ![](images/playlist.png)
 
 ## Playlists