Initial API structre

src/data/calendar.rs

@@ -0,0 +1,24 @@
+use crate::data::TaskView;
+
+/// A Caldav Calendar
+pub struct Calendar {
+    name: String,
+
+    tasks: Vec<TaskView>,
+}
+
+impl Calendar {
+    pub fn name() -> String {
+        self.name
+    }
+
+    pub fn tasks() -> Vec<TaskView> {
+        self.tasks
+    }
+}
+
+impl Drop for Calendar {
+    fn drop(&mut self) {
+        // TODO: display a warning in case some TaskViews still have a refcount > 0
+    }
+}