rewrite ranks list

src/main/java/sh/okx/rankup/ranks/RankElement.java

@@ -0,0 +1,31 @@
+package sh.okx.rankup.ranks;
+
+import lombok.Getter;
+
+import java.util.Objects;
+
+@Getter
+public class RankElement<T extends Rank> {
+  private boolean rootNode = true;
+  private final T rank;
+  private RankElement<T> next;
+
+  public RankElement(T rank, RankElement<T> next) {
+    Objects.requireNonNull(rank);
+    this.rank = rank;
+    this.next = next;
+  }
+
+  public void setRootNode(boolean rootNode) {
+    this.rootNode = rootNode;
+  }
+
+  public boolean hasNext() {
+    return next != null;
+  }
+
+  public void setNext(RankElement<T> next) {
+    this.next = next;
+    this.next.setRootNode(false);
+  }
+}