Add support for end date to adventure

frontend/src/lib/components/AdventureCard.svelte

@@ -221,7 +221,14 @@
 		{#if adventure.date && adventure.date !== ''}
 			<div class="inline-flex items-center">
 				<Calendar class="w-5 h-5 mr-1" />
-				<p>{new Date(adventure.date).toLocaleDateString(undefined, { timeZone: 'UTC' })}</p>
+				<p>
+					{new Date(adventure.date).toLocaleDateString(undefined, {
+						timeZone: 'UTC'
+					})}{adventure.end_date && adventure.end_date !== ''
+						? ' - ' +
+							new Date(adventure.end_date).toLocaleDateString(undefined, { timeZone: 'UTC' })
+						: ''}
+				</p>
 			</div>
 		{/if}
 		{#if adventure.activity_types && adventure.activity_types.length > 0}

frontend/src/lib/components/AdventureModal.svelte

@@ -34,6 +34,7 @@
 		name: adventureToEdit?.name || '',
 		type: adventureToEdit?.type || 'visited',
 		date: adventureToEdit?.date || null,
+		end_date: adventureToEdit?.end_date || null,
 		link: adventureToEdit?.link || null,
 		description: adventureToEdit?.description || null,
 		activity_types: adventureToEdit?.activity_types || [],
@@ -286,6 +287,14 @@
 
 	async function handleSubmit(event: Event) {
 		event.preventDefault();
+
+		if (adventure.date && adventure.end_date) {
+			if (new Date(adventure.date) > new Date(adventure.end_date)) {
+				addToast('error', 'Start date must be before end date');
+				return;
+			}
+		}
+
 		console.log(adventure);
 		if (adventure.id === '') {
 			let res = await fetch('/api/adventures', {
@@ -374,7 +383,7 @@
 					</div>
 
 					<div>
-						<label for="date">Date</label><br />
+						<label for="date">Date (or start date)</label><br />
 						<input
 							type="date"
 							id="date"
@@ -385,6 +394,18 @@
 							class="input input-bordered w-full"
 						/>
 					</div>
+					<div>
+						<label for="end_date">End Date</label><br />
+						<input
+							type="date"
+							id="end_date"
+							name="end_date"
+							min={startDate || ''}
+							max={endDate || ''}
+							bind:value={adventure.end_date}
+							class="input input-bordered w-full"
+						/>
+					</div>
 					<div>
 						<!-- link -->
 						<div>

frontend/src/lib/components/NewCollection.svelte

@@ -9,7 +9,7 @@
 
 	let newCollection: Collection = {
 		user_id: NaN,
-		id: NaN,
+		id: '',
 		name: '',
 		description: '',
 		adventures: [] as Adventure[],
@@ -41,6 +41,12 @@
 		const form = event.target as HTMLFormElement;
 		const formData = new FormData(form);
 
+		// make sure that start_date is before end_date
+		if (new Date(newCollection.start_date ?? '') > new Date(newCollection.end_date ?? '')) {
+			addToast('error', 'Start date must be before end date');
+			return;
+		}
+
 		const response = await fetch(form.action, {
 			method: form.method,
 			body: formData