create role teacher to authenticate

spec/shared/contexts.rb

@@ -7,9 +7,10 @@ RSpec.shared_context "authenticate_user", shared_context: :metadata do
   let(:auth_client) { @auth_headers['client'] }
   let(:uid) { @auth_headers['uid'] }
   let(:access_token) { @auth_headers['access-token'] }
+  let(:role) { Role.all }
 
   before do
-    @user = create(:user) 
+    @user = create(:user, roles: [role.find_by(name: 'teacher')])
     @auth_headers = @user.create_new_auth_token
   end