add API comments

src/rules.ts

@@ -1,6 +1,9 @@
 export type TargetRole = { guild_id: string; role_id: string };
 type SerializedRule = { group_id: string; target_role: TargetRole };
 
+/**
+ * A set of rules for associating CRI groups with Discord roles.
+ */
 export class RuleSet {
 	private rules;
 
@@ -8,6 +11,9 @@ export class RuleSet {
 		this.rules = new Map<string, TargetRole[]>();
 	}
 
+	/**
+	 * Reads a RuleSet from a JSON serialized file.
+	 */
 	public static async from_file(path: string) {
 		const result = new RuleSet();
 		const file_content = await Deno.readTextFile(path);
@@ -16,10 +22,16 @@ export class RuleSet {
 		return result;
 	}
 
+	/**
+	 * Gets which Discord roles must be assigned to a user which is part of a given CRI group.
+	 */
 	public roles_for_group(group_id: string) {
 		return this.rules.get(group_id) ?? [];
 	}
 
+	/**
+	 * Number of managed Discord roles.
+	 */
 	public size() {
 		let result = 0;
 		for (const roles of this.rules.values()) result += roles.length;