set a language flag in database

spec/features/support_spec.rb

@@ -21,6 +21,7 @@ feature 'Support announcement' do
     supporter = Supporter.find_by(email: 'blocher@blocher.ch')
     expect(supporter.coordinates).to eq [8.618589100000001, 47.2926304]
     expect(supporter.comments).to eq 'Test text'
+    expect(supporter.language).to eq 'de'
   end
 
   scenario 'A bot tries to enter data' do

spec/models/supporter_spec.rb

@@ -10,6 +10,7 @@ describe Supporter do
   it { is_expected.to validate_uniqueness_of(:email) }
   it { is_expected.to validate_presence_of(:support) }
   it { is_expected.to validate_presence_of(:age_category) }
+  it { is_expected.to validate_presence_of(:language) }
 
   describe '.counter' do
     it 'counts only from a certain number on' do