Merge pull request #36 from asmasma21/master

Adding requirements file #34
Merge pull request #37 from asmasma21/master

 Updating the Readme for virutal_env #35
 Updating the Readme for virutal_env #35
Update requirements.txt
Merge pull request #38 from oussemos/master

Adding 'requests' to requirements.txt
Update slides.py : Checking sqlalchemy Integrity
Merge pull request #40 from oussemos/master

Update slides.py : Checking sqlalchemy Integrity
Fixing #28 : add category feature
Merge pull request #44 from melekJe/issue_28

Fixing #28 : add category feature
Merge branch 'master' of https://github.com/asmasma21/slides-moztn
Merge https://github.com/moztn/slides-moztn