docs: diagrams for unit of work, update method, and value object

unit-of-work/README.md

@@ -29,6 +29,10 @@ In plain words
 
 > Maintains a list of objects affected by a business transaction and coordinates the writing out of changes and the resolution of concurrency problems.
 
+Flowchart
+
+![Unit of Work Pattern Flowchart](./etc/unit-of-work-flowchart.png)
+
 ## Programmatic Example of Unit of Work Pattern in Java
 
 Arms dealer has a database containing weapon information. Merchants all over the town are constantly updating this information causing a high load on the database server. To make the load more manageable we apply to Unit of Work pattern to send many small updates in batches.

update-method/README.md

@@ -35,6 +35,10 @@ gameprogrammingpatterns.com says
 
 > The game world maintains a collection of objects. Each object implements an update method that simulates one frame of the object’s behavior. Each frame, the game updates every object in the collection.
 
+Sequence diagram
+
+![Update Method Sequence Diagram](./etc/update-method-sequence-diagram.png)
+
 ## Programmatic Example of Update Method Pattern in Java
 
 The Update Method design pattern is a behavioral pattern that simulates a collection of independent game or application objects by telling each to process one frame of behavior at a time. This pattern is commonly used in game development, where each object in the game world needs to be updated once per frame.

value-object/README.md

@@ -43,6 +43,10 @@ Wikipedia says
 
 > In computer science, a value object is a small object that represents a simple entity whose equality is not based on identity: i.e. two value objects are equal when they have the same value, not necessarily being the same object.
 
+Flowchart
+
+![Value Object Pattern Flowchart](./etc/value-object-flowchart.png)
+
 ## Programmatic Example of Value Object Pattern in Java
 
 There is a class for hero statistics in a role-playing game. The statistics contain attributes such as strength, intelligence, and luck. The statistics of different heroes should be equal when all the attributes are equal.