SQLSTATE[HY000]: General error: 1364 Field 'category' doesn't have a default value (SQL: insert into `posts`

i recently start with laravel i try to create record by add values and but i get this error

QueryException in Connection.php line 647:
SQLSTATE[HY000]: General error: 1364 Field 'category' doesn't have a 
default value (SQL: insert into `posts` (`title`, `content`, 
`updated_at`, `created_at`) values (tip, tip, 2017-02-21 10:25:28, 
2017-02-21 10:25:28))

can anyone tell me where is my error

via Chebli Mohamed