Added code to exzbikes controller to automatically convert miles into
kilometers before saving into the database.  Should add some additional
code in the response view which displays the successiful addition in
miles.

 On branch master
 Your branch is up-to-date with 'origin/master'.

 Changes to be committed:
	modified:   exzerco-mate-webui/Gemfile
	modified:   exzerco-mate-webui/Gemfile.lock
	modified:   exzerco-mate-webui/app/controllers/exzbikes_controller.rb
	modified:   exzerco-mate-webui/app/models/exzbike.rb
	modified:   exzerco-mate-webui/app/views/exzbikes/_form.html.erb
Screwed up and removed id in exzbikes table, then realized that this was
a bad idea and put it back.  Also added a gem for composite primary
keys to be possibly used in exzweights.

 On branch master
 Your branch is up-to-date with 'origin/master'.

 Changes to be committed:
	modified:   Gemfile
	modified:   Gemfile.lock
	new file:   db/migrate/20140602161910_intro_pri_key.rb
	new file:   db/migrate/2014060216400_return_id.rb
	modified:   db/schema.rb