Added RegistrableCategory

loader/src/main/kotlin/com/willfp/libreforge/loader/configs/RegistrableCategory.kt

@@ -0,0 +1,32 @@
+package com.willfp.libreforge.loader.configs
+
+import com.willfp.eco.core.registry.Registrable
+import com.willfp.eco.core.registry.Registry
+
+/**
+ * A shorthand way of creating config categories that have their own registries.
+ */
+abstract class RegistrableCategory<T : Registrable>(
+    id: String,
+    directory: String
+) : ConfigCategory(id, directory) {
+    /**
+     * The registry.
+     */
+    protected val registry = Registry<T>()
+
+    /**
+     * Get an element by [id].
+     */
+    operator fun get(id: String?): T? = getByID(id)
+
+    /**
+     * Get an element by [id].
+     */
+    fun getByID(id: String?): T? = id?.let { registry[id] }
+
+    /**
+     * Get all elements.
+     */
+    fun values(): Set<T> = registry.values()
+}