Make channel colour optional

Author: moonfloof

README.md

@@ -30,7 +30,8 @@ Options:
 * `channels`, an array of objects, where:
   * `name` is the channel name, displayed on screen
   * `file` is a path name to the audio file, and
-  * `colour` contains the Red, Green, and Blue colour values (0-255).
+  * `colour` (optional) - contains the Red, Green, and Blue colour values
+    (0-255). Defaults to black, ie. `[0, 0, 0]`
 * `video_file_out` is a path name to the video that will be output.
 
 ```json

src/data/song.rs

@@ -18,6 +18,9 @@ use symphonia::core::{
 pub struct Channel {
 	pub name: String,
 	pub file: String,
+
+	/// Colour is optional, and will default to black, ie. [0,0,0]
+	#[serde(default)]
 	pub colour: RGB,
 
 	#[serde(skip)]