refactoring models and creating migrations to use relational database
add relation between connections and webhooks
add relation between product and connection, to know which connectio modify the model
includes load ruby scripts in lib folder
Merge branch 'feature/pg' of https://github.com/openjaf/cenit into feature/pg

Conflicts:
	Gemfile
	Gemfile.lock
	app/models/user.rb
	config/initializers/devise.rb
	db/schema.rb