Add simple search feature

[asakura42]

It will be great if your kanban will have simple stupid search feature. For example '/' will trigger search and after it only filtered tasks will be shown. It's nice also to have bind to revert all search filtering and show all tasks again. I use your kanban about a year and searching is very critical if there are many tasks. Even more critical than tags hehe.

[singalhimanshu]

@asakura42 thanks for the input I'll try to implement this feature as soon as I get some time to work on this project again. Let me know if you want to give a try to implement this feature.