Write default config if it doesn't exist

backend/sync_server/src/config/database_config.rs

@@ -21,3 +21,12 @@ fn default_max_connections() -> u32 {
     debug!("Using default max connections: {}", DEFAULT_MAX_CONNECTIONS);
     DEFAULT_MAX_CONNECTIONS
 }
+
+impl Default for DatabaseConfig {
+    fn default() -> Self {
+        Self {
+            sqlite_url: default_sqlite_url(),
+            max_connections: default_max_connections(),
+        }
+    }
+}

backend/sync_server/src/config/server_config.rs

@@ -31,3 +31,13 @@ fn default_max_body_size_mb() -> usize {
     );
     DEFAULT_MAX_BODY_SIZE_MB
 }
+
+impl Default for ServerConfig {
+    fn default() -> Self {
+        Self {
+            host: default_host(),
+            port: default_port(),
+            max_body_size_mb: default_max_body_size_mb(),
+        }
+    }
+}

backend/sync_server/src/config/user_config.rs

@@ -1,6 +1,6 @@
 use serde::{Deserialize, Serialize};
 
-#[derive(Debug, Deserialize, Serialize, Clone)]
+#[derive(Debug, Deserialize, Serialize, Clone, Default)]
 pub struct UserConfig {
     #[serde(default = "Vec::new")]
     pub users: Vec<User>,