fix: give unneeded fields default values

convenient when composing an json:icf file by hand

src/icf/models.rs

@@ -26,14 +26,20 @@ pub struct IcfInnerData {
 
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct IcfOptionData {
+    #[serde(default = "empty_string")]
     pub app_id: String,
+
     pub option_id: String,
+    
+    #[serde(default = "empty_version")]
     pub required_system_version: Version,
+    
     pub datetime: NaiveDateTime,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct IcfPatchData {
+    #[serde(default = "empty_string")]
     pub id: String,
 
     pub sequence_number: u8,
@@ -90,3 +96,11 @@ impl IcfData {
         }
     }
 }
+
+fn empty_string() -> String {
+    String::new()
+}
+
+fn empty_version() -> Version {
+    Version { major: 0, minor: 0, build: 0 }
+}