[12.0][MIG] Migrate module sql_request_abstract to v12

sql_request_abstract/readme/USAGE.rst

@@ -0,0 +1,11 @@
+Inherit the model:
+
+    from odoo import models
+
+    class MyModel(models.model)
+        _name = 'my.model'
+        _inherit = ['sql.request.mixin']
+
+        _sql_request_groups_relation = 'my_model_groups_rel'
+
+        _sql_request_users_relation = 'my_model_users_rel'