Apply Rails/FindBy rubocop rule

We were already using it in most places.

.rubocop.yml

@@ -27,9 +27,6 @@ Rails/EnvironmentComparison:
 Rails/Exit:
   Enabled: true
 
-Rails/FindBy:
-  Enabled: true
-
 Rails/FindEach:
   Enabled: true
 

.rubocop_basic.yml

@@ -156,6 +156,9 @@ Rails/ApplicationRecord:
 Rails/Date:
   Enabled: true
 
+Rails/FindBy:
+  Enabled: true
+
 Rails/HttpPositionalArguments:
   Enabled: true
 

app/models/budget/ballot.rb

@@ -68,7 +68,7 @@ class Budget
 
     def heading_for_group(group)
       return nil unless has_lines_in_group?(group)
-      investments.where(group: group).first.heading
+      investments.find_by(group: group).heading
     end
 
     def casted_offline?

app/models/concerns/relationable.rb

@@ -6,7 +6,7 @@ module Relationable
   end
 
   def find_related_content(relationable)
-    RelatedContent.where(parent_relationable: self, child_relationable: relationable).first
+    RelatedContent.find_by(parent_relationable: self, child_relationable: relationable)
   end
 
   def relationed_contents

app/models/legislation/question.rb

@@ -30,7 +30,7 @@ class Legislation::Question < ApplicationRecord
   end
 
   def answer_for_user(user)
-    answers.where(user: user).first
+    answers.find_by(user: user)
   end
 
   def comments_for_verified_residents_only?

app/models/newsletter.rb

@@ -62,7 +62,7 @@ class Newsletter < ApplicationRecord
     end
 
     def log_delivery(recipient_email)
-      user = User.where(email: recipient_email).first
+      user = User.find_by(email: recipient_email)
       Activity.log(user, :email, self)
     end
 end

app/models/notification.rb

@@ -45,7 +45,7 @@ class Notification < ApplicationRecord
   end
 
   def self.existent(user, notifiable)
-    unread.where(user: user, notifiable: notifiable).first
+    unread.find_by(user: user, notifiable: notifiable)
   end
 
   def notifiable_action

app/models/officing/residence.rb

@@ -69,8 +69,7 @@ class Officing::Residence
   end
 
   def find_user_by_document
-    User.where(document_number: document_number,
-               document_type:   document_type).first
+    User.find_by(document_number: document_number, document_type: document_type)
   end
 
   def residence_in_madrid
@@ -96,7 +95,7 @@ class Officing::Residence
   end
 
   def geozone
-    Geozone.where(census_code: district_code).first
+    Geozone.find_by(census_code: district_code)
   end
 
   def district_code

app/models/poll/ballot.rb

@@ -22,11 +22,11 @@ class Poll::Ballot < ApplicationRecord
   end
 
   def ballot
-    Budget::Ballot.where(poll_ballot: self).first
+    Budget::Ballot.find_by(poll_ballot: self)
   end
 
   def find_investment(investment_id)
-    ballot.budget.investments.where(id: investment_id).first
+    ballot.budget.investments.find_by(id: investment_id)
   end
 
   def not_already_added?(investment)

app/models/poll/booth.rb

@@ -23,7 +23,7 @@ class Poll
     end
 
     def assignment_on_poll(poll)
-      booth_assignments.where(poll: poll).first
+      booth_assignments.find_by(poll: poll)
     end
   end
 end

app/models/poll/voter.rb

@@ -56,7 +56,7 @@ class Poll
       def fill_stats_fields
         if in_census?
           self.gender = census_api_response.gender
-          self.geozone_id = Geozone.select(:id).where(census_code: census_api_response.district_code).first&.id
+          self.geozone_id = Geozone.select(:id).find_by(census_code: census_api_response.district_code)&.id
           self.age = voter_age(census_api_response.date_of_birth)
         end
       end

app/models/setting.rb

@@ -35,7 +35,7 @@ class Setting < ApplicationRecord
     end
 
     def []=(key, value)
-      setting = where(key: key).first || new(key: key)
+      setting = find_by(key: key) || new(key: key)
       setting.value = value.presence
       setting.save!
       value
@@ -50,7 +50,7 @@ class Setting < ApplicationRecord
     end
 
     def remove(key)
-      setting = where(key: key).first
+      setting = find_by(key: key)
       setting.destroy if setting.present?
     end
 

app/models/signature.rb

@@ -36,7 +36,7 @@ class Signature < ApplicationRecord
   end
 
   def assign_signature_to_vote
-    vote = Vote.where(votable: signable, voter: user).first
+    vote = Vote.find_by(votable: signable, voter: user)
     vote&.update!(signature: self)
   end
 
@@ -55,7 +55,7 @@ class Signature < ApplicationRecord
       email: nil,
       date_of_birth: @census_api_response.date_of_birth,
       gender: @census_api_response.gender,
-      geozone: Geozone.where(census_code: @census_api_response.district_code).first
+      geozone: Geozone.find_by(census_code: @census_api_response.district_code)
     }
     User.create!(user_params)
   end
@@ -84,7 +84,7 @@ class Signature < ApplicationRecord
   end
 
   def set_user
-    user = User.where(document_number: document_number).first
+    user = User.find_by(document_number: document_number)
     update(user: user)
   end
 

app/models/user.rb

@@ -237,8 +237,8 @@ class User < ApplicationRecord
   end
 
   def take_votes_if_erased_document(document_number, document_type)
-    erased_user = User.erased.where(document_number: document_number)
-                             .where(document_type: document_type).first
+    erased_user = User.erased.find_by(document_number: document_number,
+                                      document_type: document_type)
     if erased_user.present?
       take_votes_from(erased_user)
       erased_user.update!(document_number: nil, document_type: nil)
@@ -345,8 +345,8 @@ class User < ApplicationRecord
   def self.find_for_database_authentication(warden_conditions)
     conditions = warden_conditions.dup
     login = conditions.delete(:login)
-    where(conditions.to_hash).where(["lower(email) = ?", login.downcase]).first ||
-    where(conditions.to_hash).where(["username = ?", login]).first
+    where(conditions.to_hash).find_by(["lower(email) = ?", login.downcase]) ||
+    where(conditions.to_hash).find_by(["username = ?", login])
   end
 
   def self.find_by_manager_login(manager_login)

app/models/verification/email.rb

@@ -19,7 +19,7 @@ class Verification::Email
   end
 
   def user
-    User.where(document_number: verified_user.document_number).first
+    User.find_by(document_number: verified_user.document_number)
   end
 
   def generate_token

app/models/verification/management/email.rb

@@ -13,7 +13,7 @@ class Verification::Management::Email
   delegate :username, to: :user, allow_nil: true
 
   def user
-    @user ||= User.where(email: email).first
+    @user ||= User.find_by(email: email)
   end
 
   def user?

app/models/verification/residence.rb

@@ -61,7 +61,7 @@ class Verification::Residence
   end
 
   def geozone
-    Geozone.where(census_code: district_code).first
+    Geozone.find_by(census_code: district_code)
   end
 
   def district_code

app/models/widget/feed.rb

@@ -8,7 +8,7 @@ class Widget::Feed < ApplicationRecord
   end
 
   def setting
-    Setting.where(key: "homepage.widgets.feeds.#{kind}").first
+    Setting.find_by(key: "homepage.widgets.feeds.#{kind}")
   end
 
   def self.active