CreateRole

[HttpPost("Roles")]
public async Task<IActionResult> CreateRole(string roleName)
{
    if(string.IsNullOrWhiteSpace(roleName))
    {
        return BadRequest("Role name should be provided.");
    }

    var newRole = new Role
    {
        Name = roleName
    };

    var roleResult = await _roleManager.CreateAsync(newRole);

    if (roleResult.Succeeded)
    {
        return Ok();
    }

    return Problem(roleResult.Errors.First().Description, null, 500);
}