Issue 213: Solved missing key warning

This commit solves a react warning due to missing key on
list elements. It uses the comment url as key, as there
it no expectation that the same comment will appear twice in
the same replies list.

ui/src/components/Comments/index.tsx

@@ -78,7 +78,7 @@ class Comment extends React.PureComponent<ICommentProps> {
                 </summary>
             }
             {!this.props.comment.repliesError && this.props.comment.replies && <div>
-                {this.props.comment.replies.map((reply) => <Comment comment={reply}/>)}
+                {this.props.comment.replies.map((reply) => <Comment key={reply.url} comment={reply}/>)}
             </div>}
             {
                 this.props.comment.repliesError && <div className='contents'>Error loading replies for this comment</div>
@@ -200,7 +200,7 @@ export default class Comments extends React.PureComponent<IProps, IState> {
         <div>
             {!this.state.showComments && <button onClick={() => this.onClickShowComments()}>Show comments</button>}
             {this.state.showComments && <button onClick={() => this.onClickHideComments()}>Hide comments</button>}
-            {this.state.showComments && this.state.comments.map((comment) => <Comment comment={comment}/>)}
+            {this.state.showComments && this.state.comments.map((comment) => <Comment key={comment.url} comment={comment}/>)}
         </div>
         )
     }