Remove NUMBER_OF_PERMITTED_BOARDS from Project

We already check max boards in the create service. This is not used.

app/models/project.rb

@@ -38,7 +38,6 @@ class Project < ActiveRecord::Base
   BoardLimitExceeded = Class.new(StandardError)
 
   STATISTICS_ATTRIBUTE = 'repositories_count'.freeze
-  NUMBER_OF_PERMITTED_BOARDS = 1
   UNKNOWN_IMPORT_URL = 'http://unknown.git'.freeze
   # Hashed Storage versions handle rolling out new storage to project and dependents models:
   # nil: legacy
@@ -137,7 +136,7 @@ class Project < ActiveRecord::Base
   alias_attribute :parent_id, :namespace_id
 
   has_one :last_event, -> {order 'events.created_at DESC'}, class_name: 'Event'
-  has_many :boards, before_add: :validate_board_limit
+  has_many :boards
 
   # Project services
   has_one :campfire_service
@@ -2194,17 +2193,6 @@ class Project < ActiveRecord::Base
     "projects/#{id}/pushes_since_gc"
   end
 
-  # Similar to the normal callbacks that hook into the life cycle of an
-  # Active Record object, you can also define callbacks that get triggered
-  # when you add an object to an association collection. If any of these
-  # callbacks throw an exception, the object will not be added to the
-  # collection. Before you add a new board to the boards collection if you
-  # already have 1, 2, or n it will fail, but it if you have 0 that is lower
-  # than the number of permitted boards per project it won't fail.
-  def validate_board_limit(board)
-    raise BoardLimitExceeded, 'Number of permitted boards exceeded' if boards.size >= NUMBER_OF_PERMITTED_BOARDS
-  end
-
   def update_project_statistics
     stats = statistics || build_statistics
     stats.update(namespace_id: namespace_id)

spec/models/project_spec.rb

@@ -136,15 +136,6 @@ describe Project do
       end
     end
 
-    describe '#boards' do
-      it 'raises an error when attempting to add more than one board to the project' do
-        subject.boards.build
-
-        expect { subject.boards.build }.to raise_error(Project::BoardLimitExceeded, 'Number of permitted boards exceeded')
-        expect(subject.boards.size).to eq 1
-      end
-    end
-
     describe 'ci_pipelines association' do
       it 'returns only pipelines from ci_sources' do
         expect(Ci::Pipeline).to receive(:ci_sources).and_call_original