Paging and searching

Add paging using [kaminari](https://github.com/amatsuda/kaminari)

Add searching using [scoped_seach](https://github.com/wvanbergen/scoped_search). This allows a lot of flexibility to do searches. 

Add basic testing and do little refactor on them. 
Do not require lot of tests as `kaminari` and `scoped_search` are well tested so the aim is to test our app.