Add cli & lib crates

lib/src/category.rs

@@ -0,0 +1,27 @@
+use chrono::{DateTime, Local};
+use serde::{Deserialize, Serialize};
+use uuid::Uuid;
+
+pub type CategoryKey = Uuid;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Category {
+    /// The name of the category
+    pub name: String,
+
+    /// The description of the category
+    pub description: Option<String>,
+
+    /// The HTML color of the category in the rendered view
+    pub color: String,
+
+    /// If the session is not active, this will be None
+    pub started: Option<DateTime<Local>>,
+
+    /// The parent category of this category
+    /// If none, the category has no parent
+    pub parent: Option<CategoryKey>,
+
+    /// Whether the item has been "deleted", e.g. it shoudn't be shown in the view
+    pub deleted: bool,
+}