diff --git a/.rubocop.yml b/.rubocop.yml
index 308bd07..2dce968 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -8,6 +8,9 @@ AllCops:
     - gemfiles/*
     - spec/**/*
 
+Gemspec/DevelopmentDependencies:
+  Enabled: false
+
 Style/Documentation:
   Enabled: false
 
diff --git a/lib/ajax-datatables-rails/base.rb b/lib/ajax-datatables-rails/base.rb
index da6624a..be075f3 100644
--- a/lib/ajax-datatables-rails/base.rb
+++ b/lib/ajax-datatables-rails/base.rb
@@ -101,23 +101,15 @@ def column_data(column)
 
     # helper methods
     def connected_columns
-      @connected_columns ||= begin
-        view_columns.keys.map do |field_name|
-          datatable.column_by(:data, field_name.to_s)
-        end.compact
-      end
+      @connected_columns ||= view_columns.keys.map { |field_name| datatable.column_by(:data, field_name.to_s) }.compact
     end
 
     def searchable_columns
-      @searchable_columns ||= begin
-        connected_columns.select(&:searchable?)
-      end
+      @searchable_columns ||= connected_columns.select(&:searchable?)
     end
 
     def search_columns
-      @search_columns ||= begin
-        searchable_columns.select(&:searched?)
-      end
+      @search_columns ||= searchable_columns.select(&:searched?)
     end
 
     def sanitize_data(data)
diff --git a/lib/ajax-datatables-rails/datatable/column.rb b/lib/ajax-datatables-rails/datatable/column.rb
index 4b23d4a..921c76c 100644
--- a/lib/ajax-datatables-rails/datatable/column.rb
+++ b/lib/ajax-datatables-rails/datatable/column.rb
@@ -100,7 +100,7 @@ def casted_column
       end
 
       def validate_settings!
-        raise AjaxDatatablesRails::Error::InvalidSearchColumn, "Unknown column. Check that `data` field is filled on JS side with the column name" if column_name.empty?
+        raise AjaxDatatablesRails::Error::InvalidSearchColumn, 'Unknown column. Check that `data` field is filled on JS side with the column name' if column_name.empty?
         raise AjaxDatatablesRails::Error::InvalidSearchColumn, "Check that column '#{column_name}' exists in view_columns" unless valid_search_column?(column_name)
         raise AjaxDatatablesRails::Error::InvalidSearchCondition, cond unless valid_search_condition?(cond)
       end