Fix Eq query

Signed-off-by: Etzelia <etzelia@hotmail.com>

model/django/django.go

@@ -25,7 +25,7 @@ func (db *Builder) QueryString() string {
 }
 
 func (db *Builder) Eq(field Field, value interface{}) *Builder {
-	db.Params = append(db.Params, fmt.Sprintf("%__eq=%v", field, value))
+	db.Params = append(db.Params, fmt.Sprintf("%s__eq=%v", field, value))
 	return db
 }