Implement task API with input validation; implement error handling; refactoring

api_tests/tasks.http

@@ -0,0 +1,28 @@
+### Fetch all tasks
+GET {{api_host}}/api/tasks
+
+
+### Fetch one task
+GET {{api_host}}/api/tasks/1
+
+
+### Create new task
+POST {{api_host}}/api/tasks
+Content-Type: application/json
+
+{
+  "title": "Some test task"
+}
+
+
+### Update task
+PATCH {{api_host}}/api/tasks/1
+Content-Type: application/json
+
+{
+  "description": "Update!"
+}
+
+
+### Delete task
+DELETE {{api_host}}/api/tasks/10