Two submit buttons 'save' and 'save and new' in CodeIgniter - save

Question

If I click save I want to redirect to userslist view and when I click save and new I want to redirect again to add users view and script "save successfully" but it is too hard to solve. Does anybody have an idea to fix this issue?
This is my view in add form.
<form method="post" action="<?php echo site_url('users/add')?>" >
<label>FirstName</label>
<input type="text" name="first_name" placeholder="Firstname"required>
<label>LastName</label>
<input type="text" name="last_name" placeholder="Lastname"required>
<label>Email</label>
<input type="email" name="email" placeholder="Email"required>
<label>Username</label>
<input type="Username" name="username" placeholder="Username"required>
<label>Password</label>
<input type="password" name="password" id="password" placeholder="Password"required>
<label>Confirm Password</label>
<input type="password" placeholder="Confirm Password" id="confirm_password" required>
<label>Permissions</label>
<input type="text" name="permissions" placeholder="Permissions"required>
<label>Role ID</label>
<input type="text"required name="role_id" placeholder="Role ID"required>
<label>Created By</label>
<input type="text"required name="created_by" placeholder="Created By"required>
<button type="submit" value="formSave">SAVE</button>
<button type="submit" value="formSaveNew">SAVE AND ADD NEW</button>
This is my controller to add
public function add()
{
$this->data['page_title'] = "Add User";
$input_data = $this->input->post();
if(!empty($input_data)){
$this->User_model->insert($input_data);
redirect('/users');
} else {
$this->load->view('templates/master', $this->data);
}
}