Add assets and update README.md

Co-authored-by: LucasCatolino <lcatolino@fi.uba.ar>
Co-authored-by: KuJo7 <joel.k2010@gmail.com>

.gitignore

@@ -192,5 +192,3 @@ nb-configuration.xml
 ## Miscellaneous
 ##############################
 *.log
-
-*.png

README.md

@@ -53,6 +53,10 @@ The `App` class demonstrates the following functionalities:
 - Modifying the books capacity using decorators.
 - Iterating over the library items using the Iterator pattern.
 
+## Note
+
+In the `./assets/` directory, you can find a UML diagram of the project and the document `adp_hw1.pdf`, which contains a brief description of the application idea and discussions about design decisions and design patterns used.
+
 ## Contributors
 
 - Lucas Catolino