fixed review comments and add UserGuide

UserGuide.md

@@ -0,0 +1,9 @@
+UserGuide.md:
+
+In test/goodQuestion.js, you are able to run a test that checks that, when clicking the Green Check-Mark next to the upvote
+button on any particular post, it is marked as a "Good Question" by NodeBB. This test is sufficient for covering the change I made
+as this is the only feature implemented; I did not work on "un-voting" or any other feature.
+
+![Post](/img1.png)
+
+![Voting](/img2.png)

nodebb-theme-harmony/scss/topic.scss

@@ -65,7 +65,6 @@ body.template-topic {
 			[component="post/upvote"],
 			[component="post/downvote"],
 			[component="post/goodquestion"] {
-
 				&.upvoted,
 				&.downvoted,
 				&.goodquestioned {

public/language/en-GB/admin/manage/privileges.json

@@ -37,6 +37,7 @@
 	"view-deleted": "View Deleted Posts",
 	"upvote-posts": "Upvote Posts",
 	"downvote-posts": "Downvote Posts",
+	"goodquestion-posts": "Mark as Good Question",
 	"delete-topics": "Delete Topics",
 	"purge": "Purge",
 	"moderate": "Moderate",

src/posts/votes.js

@@ -116,6 +116,7 @@ module.exports = function (Posts) {
 		}
 	}
 
+	// Marks the specified post as a good question if the user has the required privileges and isn't already marking it.
 	Posts.goodquestion = async function (pid, uid) {
 		const canMark = await privileges.posts.can('posts:goodquestion', pid, uid);
 		if (!canMark) {
@@ -128,6 +129,7 @@ module.exports = function (Posts) {
 		return { goodquestion: true };
 	};
 
+	// Checks if a user has already marked the specified post as a good question by verifying their membership in a corresponding database set.
 	Posts.hasMarkedGood = async function (pid, uid) {
 		if (parseInt(uid, 10) <= 0) {
 			return { goodquestion: false };