Actually read out rule_id in PushRule's from_json

lib/structs/pushrules.cpp

@@ -98,6 +98,7 @@ to_json(nlohmann::json &obj, const PushRule &rule)
 void
 from_json(const nlohmann::json &obj, PushRule &rule)
 {
+    rule.rule_id  = obj.value("rule_id", "");
     rule.default_ = obj.value("default", false);
     rule.enabled  = obj.value("enabled", true);
 

tests/pushrules.cpp

@@ -227,6 +227,7 @@ TEST(Pushrules, GlobalRuleset)
     EXPECT_EQ(rules.global.sender.size(), 0);
     EXPECT_EQ(rules.global.underride.size(), 6);
     EXPECT_EQ(rules.global.underride[0].conditions.at(0).key, "type");
+    EXPECT_EQ(rules.global.content[0].rule_id, ".m.rule.contains_user_name");
 }
 
 TEST(Pushrules, GetGlobalRuleset)