Server Side
PDF with Prawn setup

Added test method and route to verify that prawn is working.

Clients search by filter

Updated ClientsController so that a query can be passed to
ClientsController#index. The query allows searching by ragione_sociale
or id via a like SQL.

Client Side
ClientsController, ClientsSvc and related templates
Adjusted in order to allow Clients list filtering.
Server Side
Interventions Controller

Added code to allow filtering of interventions based on intervention's
Id, Client, User.

Client Side
Tweaked interventions and edit_interventions controller, as well as,
InterventionsSvc in order to deal with user's query.
A user can now search for an intervention via:
- Id
- User who performed the intervention (user's email)
- Client
Server Side
Background jobs
Added sessions management jobs via Whenever gem.

Sessions are expired after 5 minutes of inactivity or 1 day of life.

Client Side
Removed search from locations.
The rationale behind this is that a client, will probably not have more
than a bunch of locations. Most probably they will easily fit on one
page too.
Server Side
SessionsController
Added authentication status check
Clients can now call api/v1/sessions/authenticated_user in order to get
the current session user if any.
When there's no currently authenticated user the reply will be user: ''.

Client Side
MainController and SessionsSvc
MainController now queries backend upon initialization in order to find
if there's any current logged in user.
This prevents a bug in the UI when the user closes the browser window
without doing a logout. In that case, the session on the server doesn't
get destroyed and if the user goes back to the app, the navbar behaved
like there was no current user logged in, while everything else worked
properly since the old session was still valid.