typo

src/main/java/de/anxietyprime/swajodel/JodelPost.java

@@ -54,7 +54,7 @@ public class JodelPost {
 
     // add a comment if it is really a comment
     public boolean addComment(JodelPost post, long parent) {
-        // check if the post a direct comment
+        // check if the post is a direct comment
         if (parent == this.id) {
             // add the comment
             this.comments.add(post);