Refactor admin/call_for_booth controller

app/models/booth.rb

@@ -4,13 +4,13 @@ class Booth < ActiveRecord::Base
   has_many :users, through: :booth_requests
 
   validates :title,
-            uniqueness: { case_sensitive: fasle},
+            uniqueness: { case_sensitive: false },
             presence: true
 
   validates :description,
             :reasoning,
             :state,
-            :logo_link
+            :logo_link,
             :conference_id,
             presence: true
 end

app/models/call_for_booth.rb

@@ -1,8 +1,6 @@
 class CallForBooth < ActiveRecord::Base
   belongs_to :conference
 
-  has_one :conference
-
   validates :start_date, :end_date, :booth_limit, presence: true
   validate :before_end_of_conference
   validate :start_date_before_end_date