Add two new assignment operators

README.md

@@ -140,6 +140,25 @@ For example:
 
 If you however try to use these kinds of assignment operators on variabes which have not been initialized with a value yet, an exception will occur.
 
+There are also two kinds of "special" assignment operators:
+- `++` increment unary operator functions like `+= 1`
+- `--` decrement unary operator functions like `-= 1`
+
+for example:
+```
+let i = 0;
+let first = i++; // first becomes 0, i increments to 1
+let second = i--; // second becomes 1, i decrements back to 0.
+```
+
+All assignment operators return the value the assignee (leftside of the operator) was before the operator. For more examples:
+
+```
+let test = 0;
+let new = (test = 2); // new becomes 0, test becomes 2
+let another = (new += 5); /// another becomes 0, new becomes 5.
+```
+
 ## Scopes
 Scopes are areas of code surrounded by brackets `{}`. E.g.
 ```