[#62586254] add env var validator
[#62586254] refactor User#ip attribution in CampaignSpreader#create
[#62586254] add campaign_id to CampaignSpreader
[#62586254] add shoulda-matchers
[#62586254] add has_many campaign_spreaders to Campaign
[#62586254] add instance for campaign at Campaigns#show action
[#62586254] add relations to CampaignSpreader
[#62586254] associate CampaignSpreader to the Campaign in CampaignSpreader#create
[#62586254] remove pending test
[#62586254] remove pending test
[#62586254] remove pending test
[#62586254] add test for User