68355394 storing organizations in DB

https://www.pivotaltracker.com/story/show/68355394

- added Organisation model
- added ImportOrganisations task
- added Rspec tests for Organisation model and ImportOrganizations task
- corrected some existing Rspec tests
- added some gems : ancestry, friendly_id, webmock, fakefs, launchy
68355394 store organizations in db

- added rake task "rake db:populate_organisation_for_dev_env",
  which needs to populate organisation for development env
  in case if you have no ability to populate organisations
  using GOV API and 'rake organisations:inport' script
68355394 added import orgs to cron
68355394 Store needs in db

- added api_id column to Organisation model
  because needs api returns organisation_ids with ids of Organisations.
  https://github.com/alphagov/govuk_need_api/blob/master/test/functional/needs_controller_test.rb#L150
  example:
     organisation_ids: ["cabinet-office","department-for-transport"]
- corrected ImportOrganisations script (added saving of api_id)
- added ImportNeeds task
- corrected related associations ContentNeed and ContentPlanNeed
  So, these to tables stored api id of need in need_id
  Now when we store Needs in out db table it should store id of database entry
- corrected calls to needs in app
- corrected Rspec tests

Important note:
  1. migration 20140505144311_correct_needs_associations_structure.rb
    is oriented to correct Needs realated associations ContentNeed and ContentPlanNeed.
    So, it's important to have in db already populated Organisations and Needs.
    So, API_CLIENT_CREDENTIALS should not be empty if you are running it on staging or prod envs.
    If you run it in dev env - you can uncomment line 15:
      # PopulateOrganisationAndNeedForDevEnv.run
    This will populate test Organisation and Needs.

  2. In case if you already run rake db:migrate, but needs db table was empty
     - you can then run:
       rake db:import to import needs from API or
       rake db:populate_organisation_and_need_for_dev_env if you have no access to API
     - and the run:
       rake db:correct_need_associations - it will correct ContentPlanNeed and ContentNeed tables
68355394 needs - corrected tooltip
Merge pull request #66 from bitzesty/68355394-store-needs-in-db

68355394 store needs in db