port #989 to new branch due to lack of perms to fix conflicts (#1276)

ormar/fields/foreign_key.py

@@ -262,6 +262,8 @@ def ForeignKey(  # type: ignore # noqa CFQ002
     sql_nullable = kwargs.pop("sql_nullable", None)
     sql_nullable = nullable if sql_nullable is None else sql_nullable
 
+    index = kwargs.pop("index", False)
+
     validate_not_allowed_fields(kwargs)
     pk_only_model = None
     if to.__class__ == ForwardRef:
@@ -296,7 +298,7 @@ def ForeignKey(  # type: ignore # noqa CFQ002
         related_name=related_name,
         virtual=virtual,
         primary_key=False,
-        index=False,
+        index=index,
         default=None,
         server_default=None,
         onupdate=onupdate,