Add survey-slider plugin to main README

README.md

@@ -44,6 +44,7 @@ Plugin/Extension | Contributor | Description
 [survey-number](https://github.com/jspsych/jspsych-contrib/blob/main/packages/plugin-survey-number/README.md) | [Josh de Leeuw](https://github.com/jodeleeuw) | This plugin displays a survey question and collects a numeric response.
 [vsl-animate-occlusion](https://github.com/jspsych/jspsych-contrib/blob/main/packages/plugin-vsl-animate-occlusion/docs/jspsych-vsl-animate-occlusion.md#jspsych-vsl-animate-occlusion-plugin) | [Josh de Leeuw](https://github.com/jodeleeuw) | The VSL (visual statistical learning) animate occlusion plugin displays an animated sequence of shapes that disappear behind an occluding rectangle while they change from one shape to another. 
 [vsl-grid-scene](https://github.com/jspsych/jspsych-contrib/blob/main/packages/plugin-vsl-grid-scene/docs/jspsych-vsl-grid-scene.md#jspsych-vsl-grid-scene-plugin) | [Josh de Leeuw](https://github.com/jodeleeuw) | The VSL (visual statistical learning) grid scene plugin displays images arranged in a grid. 
+[survey-slider](https://github.com/jspsych/jspsych-contrib/blob/main/packages/plugin-survey-slider/README.md) | [Max Lovell](https://github.com/Max-Lovell) & [Dominique Makowski](https://github.com/DominiqueMakowski) | Add several analogue scales on the same page for use in questionnaires. 
 [html-keyboard-slider](https://github.com/jspsych/jspsych-contrib/blob/main/packages/plugin-html-keyboard-slider/docs/jspsych-html-keyboard-slider.md) | [Max Lovell](https://github.com/Max-Lovell) | Sliders which allow for keyboard responses.
 
 ## Guidelines for contributions