update README.md

Author: n1nj4t4nuk1

README.md

@@ -16,8 +16,46 @@ A collection of Value Objects to save time by generalizing types and format vali
 
 ### Int
 
+Integer numbers without a fractional component that don't support decimal points.
+
+```python
+from pyvalueobjects import Int
+
+# Creation
+my_integer = Int(9)
+
+# Getting raw value
+my_integer.value() # returns -> 9
+```
+
 ### Nullable Int
 
+Integer numbers and None.
+
+```python
+from pyvalueobjects import NullableInt
+
+# Creation
+my_integer = NullableInt(9)
+
+# Creating from None
+my_nullable_integer = NullableInt(None)
+
+# Getting raw value
+my_integer.value() # returns -> 9
+my_nullable_integer.value() # returns -> None
+```
+
 ## String value-objects
 
-### String
+### String
+
+```python
+from pyvalueobjects import String
+
+# Creation
+my_str = String('potato')
+
+# Getting raw value
+my_str.value() # returns -> 'potato'
+```