Catch database errors and prevent them from crashing the app

lib/TestTemplate.js

@@ -99,13 +99,18 @@ class TestTemplate {
 
 		const conn = await new DatabaseConnectionPool();
 
-		await conn.runQuery(sql, [
+		const result = await conn.runQuery(sql, [
 			id,
 			this.id,
 			c.id,
 			epochDate
 		]);
 
+		conn.close();
+
+		if (!result.length)
+			throw new Error('Could not assign class');
+
 		return new Test(id);
 	}
 
@@ -130,13 +135,18 @@ class TestTemplate {
 				(?, ?, ?, ?);
 		`;
 
-		await conn.runQuery(sql, [
+		const result = await conn.runQuery(sql, [
 			id,
 			a.id,
 			name,
 			maxMark
 		]);
 
+		conn.close();
+
+		if (!result)
+			throw new Error('Could not create test template');
+
 		return new TestTemplate(id);
 	}
 }