User Onboarding + Bug Fixes (#1352)

* Bump min supported date to 20 years

* Add basic onboarding

* User onboarding

* Complete onboarding flow

* Cleanup, add user profile update test

app/controllers/concerns/onboardable.rb

@@ -0,0 +1,17 @@
+module Onboardable
+  extend ActiveSupport::Concern
+
+  included do
+    before_action :redirect_to_onboarding, if: :needs_onboarding?
+  end
+
+  private
+    def redirect_to_onboarding
+      redirect_to onboarding_path
+    end
+
+    def needs_onboarding?
+      Current.user && Current.user.onboarded_at.blank? &&
+        !%w[/users /onboarding /sessions].any? { |path| request.path.start_with?(path) }
+    end
+end