Add name shortcut for ConfigGroup instances

Add .name shortcut to get the groupName class property of config group
instances.

lib/config/classes.js

@@ -112,7 +112,7 @@ class Config extends events.EventEmitter {
 
 			let group = new GroupClass();
 			await group.load(this, serializedGroup);
-			this._groups.set(GroupClass.groupName, group);
+			this._groups.set(group.name, group);
 		}
 
 		await this.init();
@@ -301,6 +301,15 @@ class ConfigGroup {
 		await this.init(config);
 	}
 
+	/**
+	 * Name of the group
+	 *
+	 * Shortcut for `group.constructor.groupName`
+	 */
+	get name() {
+		return this.constructor.groupName;
+	}
+
 	/**
 	 * Get value for field
 	 */
@@ -384,8 +393,8 @@ class ConfigGroup {
 			throw new Error(`Expected object, not ${basicType(serializedGroup)} for ConfigGroup`);
 		}
 
-		if (serializedGroup.name !== this.constructor.groupName) {
-			throw new Error(`Expected group name ${this.constructor.groupName}, not ${serializedGroup.name}`);
+		if (serializedGroup.name !== this.name) {
+			throw new Error(`Expected group name ${this.name}, not ${serializedGroup.name}`);
 		}
 
 		if (basicType(serializedGroup.fields) !== "object") {
@@ -435,7 +444,7 @@ class ConfigGroup {
 		}
 
 		return {
-			name: this.constructor.groupName,
+			name: this.name,
 			fields,
 		};
 	}

test/lib/config/classes.js

@@ -156,6 +156,14 @@ describe("lib/config/classes", function() {
 			});
 		});
 
+		describe("get name", function() {
+			it("should give the name of the group", async function() {
+				let testInstance = new TestGroup();
+				await testInstance.init();
+				assert.equal(testInstance.name, "test_group");
+			});
+		});
+
 		describe(".serialize()", function() {
 			it("should serialize a basic group", async function() {
 				let testInstance = new TestGroup();