Adds simple delete api

cookbook/src/bin/write_recipe.rs

@@ -76,7 +76,7 @@ fn main() {
     }
     let mut category_id = String::new();
     stdin().read_line(&mut category_id).unwrap();
-    let category_id = category_id.trim().parse::<i16>().expect("Could not parse id");
+    let category_id = category_id.trim().parse::<i16>().unwrap_or(0);
     builder.set_category(category_id);
 
     println!("Ingredients (empty line to finish): ");

cookbook/src/lib.rs

@@ -30,6 +30,16 @@ pub mod recipes {
         recipes.load::<Recipe>(conn)
             .expect("Error loading recipe's list")
     }
+
+    pub fn delete(conn: &SqliteConnection, recipe_id: i32) -> bool {
+        use self::schema::recipes::dsl::*;
+
+        diesel::delete(
+                recipes.filter(
+                    id.eq(recipe_id)))
+            .execute(conn)
+            .is_ok()
+    }
 }