Description:
Creates ApplicationFlow, ApplicationOperation, and ApplicationState with tests.
Example:
`rails generate flow:install` Generates: Flow: app/flows/application_flow.rb Operation: app/operations/application_operation.rb State: app/states/application_state.rb Test: spec/flows/application_flow_spec.rb Test: spec/operations/application_operation_spec.rb Test: spec/states/application_state_spec.rb