Changelog updated with 0.5.1 changes.

CHANGELOG.md

@@ -1,5 +1,14 @@
 # Changelog
 
+## 0.5.1 - 2021-05-04
+## Added
+- Message when a file cannot be retrieved.
+
+## Fixed
+- Removed excessive hash comparison when files has same name;
+- A string forgotten to set to be a f-string, so now it displays a reason of why
+  thread wasn't found.
+
 ## 0.5.0 - 2021-05-03
 ## Added
 - Now program makes use of skip_posts argument. Use CLI option `-S <number>`