Allow long strings for "context"

Adding pagination module that will have to be included
in autoload_paths.

-Paginator module is responsible for calculating and rendering a
pagination bar based on the passed parameters.
-Added rspec for Paginator.

-Add _blocks.html.erb view that renders page blocks;
-Add _paginator.html.erb view that renders the pagination panel for the
current page of a given Model.

-Added the paginator helper method to index.html.erb for Bet that
renders the pagination panel with given parameters;
-Added display_bets partial that renders all the bets in the bets
instance variable;
-Added bet partial for Bet model;