[+] image upload for reminder;
[+] displaying images on reminders list;
[+] default image;
[+] path optimization;
[+] form validation in model;
[+] interface + abstract class for reminder type models;
[+] interface + abstract class for reminder type models;
[+] interface + abstract class for reminder type models;
Merge pull request #4 from CoolEsh/image_upload

Image upload
Merge branches 'exception_handling' and 'master' of https://github.com/CoolEsh/notes into exception_handling