corrected StringLiterals

Author: JRfromAustria

.ruby-version

@@ -0,0 +1 @@
+2.6.9

lib/jsonapi/rails.rb

@@ -47,7 +47,7 @@ def self.add_errors_renderer!
         ) unless resource.is_a?(ActiveModel::Errors)
 
         errors = []
-        model = resource.instance_variable_get('@base')
+        model = resource.instance_variable_get(:@base)
 
         if respond_to?(:jsonapi_serializer_class, true)
           model_serializer = jsonapi_serializer_class(model, false)

spec/errors_spec.rb

@@ -31,7 +31,7 @@
 
       it do
         expect(response).to have_http_status(:unprocessable_entity)
-        expect(response.media_type).to eq("application/vnd.api+json")
+        expect(response.media_type).to eq('application/vnd.api+json')
         expect(response_json['errors'].size).to eq(1)
         expect(response_json['errors'][0]['status']).to eq('422')
         expect(response_json['errors'][0]['title'])

spec/fetching_spec.rb

@@ -25,7 +25,7 @@
         it do
           expect(response).to have_http_status(:ok)
           expect(response_json['data'].size).to eq(users.size)
-          expect(response.media_type).to eq("application/vnd.api+json")
+          expect(response.media_type).to eq('application/vnd.api+json')
 
           response_json['data'].each do |item|
             user = users.detect { |u| u.id == item['id'].to_i }