Merge pull request #34 from alexcodreanu86/carousel

Carousel
updated form layout
new admin can be created by existing admin
pulled out some of the logic from controller to model, rate is generated with new extra charges in case of airport and greet
base rate can be generated as well withoud adding the extra charges
trip model adds extra charges if necessary on create
email uniqueness validation added
added customer list button and add admin button
added links to add edit and delete extra charges
added routes for extra charges
added total price to trips and updated base_price
updated the schema with extra charges table
added extra charges crud
added associations and before create and before destroy logic
added index view file
add new admin form
added new extra charges edit and new functionality and forms
add extra charges migration
generated extra charges model and migration
Merge branch 'master' of http://github.com/alexcodreanu86/nitar into carousel