add uuid field

orator/schema/blueprint.py

@@ -522,6 +522,9 @@ def boolean(self, column):
         """
         return self._add_column("boolean", column)
 
+    def uuid(self, column):
+        return self._add_column('uuid', column)
+
     def enum(self, column, allowed):
         """
         Create a new enum column on the table.

orator/schema/grammars/postgres_grammar.py

@@ -215,6 +215,9 @@ def _type_timestamp(self, column):
     def _type_binary(self, column):
         return "BYTEA"
 
+    def _type_uuid(self, column):
+        return "UUID"
+
     def _modify_nullable(self, blueprint, column):
         if column.get("nullable"):
             return " NULL"