add default language

src/iotro.rs

@@ -94,6 +94,12 @@ pub const BRITISH: Language<'static> = Language {
 	questions_feedback: "Questions, Suggestions and Feedback"
 };
 
+impl Default for Language<'static> {
+	fn default() -> Self {
+		GERMAN
+	}
+}
+
 impl FromStr for Language<'static> {
 	type Err = anyhow::Error;
 

src/main.rs

@@ -154,6 +154,7 @@ struct ProjectLecture {
 	docent: String,
 	#[serde_as(as = "DisplayFromStr")]
 	date: Date,
+	#[serde(default = "Default::default")]
 	#[serde_as(as = "DisplayFromStr")]
 	lang: Language<'static>
 }