Drafted intended API for GE.

README.md

@@ -119,6 +119,28 @@ with Flow(...) as flow:
     close_ssh_tunnel.run(tunnel=tunnel)
 ```
 
+### Use Great Expectations
+
+**Run a Great Expectations validation on a MySQL query**
+
+```python
+from lolafect.connections import connect_to_mysql
+from lolafect.data_testing import run_data_test_on_mysql
+
+with Flow(...) as flow:
+    
+    a_mysql_connection = connect_to_mysql(...)
+    
+    my_query = """SELECT something FROM somewhere"""
+    my_expectations = {...} # A bunch of things you want to validate on the result of the query
+    
+    validation_results = run_validation_on_mysql(
+        mysql_connection=a_mysql_connection,
+        query=my_query,
+        expectations=my_expectations
+    )
+```
+
 ### Slack
 
 **Send a warning message to slack if your tasks fails**