Add stack model
Refactoring: add cloud on stack and remove unnecessary specs
Add protocol column on patterns table
Implement Stack#payload to create payload when configure
Split status of stack to :PENDING, :READY, :PROGRESS, :CREATE_COMPLETE and :ERROR
Add template_parameters column on System
Add Stack.created scope to retrieve created stacks
Rebuild stack observer that use system and stacks to accept optional pattern
Refactoring: add a bit spec on System#template_parameters
Change command for create patterns by packer to support optional pattern
Add StacksController
Mount StackController on /stacks
Return symbolized type on pattern
Compare symbolized status when use stored record in database
Restrict parameters when create system record by REST API
Change variable name for platform_pattern_name to pattern_name
Remove FrontendAddress from parameters that passed to optional pattern
Update status with :READY of :PENDING that is decided by type of pattern when duplicate stacks
Clear template_parameter when duplicate system
Change URL for REST API to hierarchized URL under /systems