Added publish date to topics

Conflicts:
	db/schema.rb
Added 'public' as default value to datasets access level

Conflicts:
	app/models/data_set.rb
Added figaro gem for env variables

Conflicts:
	Gemfile
User can edit inventory even if there are no topics
Removed old validations to datasets
Removed whitespaces from organizations title on rake task
Fix - Reset password from email
Added application.yml example and changed env variables names
Hardcoded HOST for test environment
Admin can see registered users sorted by creation date
Fix - Typo on test.rb ('localhost')
Merge pull request #50 from mxabierto/feature/mvp-last-details

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