code: def add_campaign(options={})
        response = connection.post do |req|
          req.url "campaigns/add", options
        end
          return_error_or_body(response, response.body.response.campaign)
      end
docs: Add a campaign
   Details on param options can be found at https://developer.foursquare.com/docs/campaigns/add
  
   @param [Hash]  options
   @option options String :specialId - required (unless the campaignId parameter has been provided). special ID
   @option options String :groupId - comma-separated list of venue group IDs (either groupId or venueId is required)
   @option options String :venueId - comma-separated list of venue IDs (either groupId or venueId is required)
   @option options Integer :endAt - DateTime when the campaign is to be automatically deactivated (seconds since epoch)
   @option options Integer :startAt - DateTime when the campaign is to be started (seconds since epoch)
   @option options String :campaignId - ID of an existing campaign to copy.