add regenerate portions when add new group memeber
small fix in show pages and add test button for settlement
add test to settle the group and release when users confirm payments
Merge branch 'master' into federico

merged manually conflicts
Conflicts:
	app/controllers/memberships_controller.rb
	app/controllers/setllements_controller.rb
	app/models/group.rb
	db/schema.rb
completed group settlements
Merge branch 'master' into federico

manual conflicts solving
Conflicts:
	app/controllers/groups_controller.rb
	app/controllers/memberships_controller.rb
	app/controllers/settlements_controller.rb
	app/views/expenses/show.html.erb
	app/views/groups/show.html.erb
Merge pull request #46 from elitenomad/federico

Federico