Update README to include instructions for using iOS predicates

Author: emil-petersen

README.md

@@ -156,6 +156,25 @@ self.assertIsInstance(els, list)
 ```
 
 
+### Finding elements by iOS predicates
+
+This method allows finding elements using iOS predicates. The methods take a
+string in the format of a predicate, including element type and the value of
+fields.
+
+Adds the methods
+`driver.find_element_by_ios_predicate` and `find_elements_by_ios_predicate`.
+
+```python
+el = self.driver.find_element_by_ios_predicate('wdName == "Buttons"')
+self.assertIsNotNone(el)
+```
+
+```python
+els = self.driver.find_elements_by_ios_predicate('wdValue == "SearchBar" AND isWDDivisible == 1')
+self.assertIsInstance(els, list)
+```
+
 ### Finding elements by Accessibility ID
 
 Allows for elements to be found using the "Accessibility ID". The methods take a