use DB;

     public function csv2sql(Request $request)
     {

        // validation
        $validator = Validator::make($request->all(), [
            'csvtext' => 'required|max:22000',
        ]);

        if ($validator->fails()) {
            return redirect('users')
                ->withInput()
                ->withErrors($validator);
        }

            $csv = $request->csvtext;
            $data = preg_split('/\s+/', $csv);
            foreach ($data as $key => $value) {
                $split = explode(",", $value);
                $username = $split[0];
                $password = $split[1];
                DB::table('users')->insert(array('username' => $username, 'password' => $password));
            }

            return redirect('/');
    }