Set redirect_to back fallback location for when no HTTP_REFERRER is set.

[despo]

Description of the issue 📄

From error log

 ActionController::RedirectBackError: No HTTP_REFERER was set in the request to this action, so redirect_to :back could not be called successfully. If this is a test, make sure to specify request.env["HTTP_REFERER"].
+
9 non-project frames
1
File "/app/vendor/bundle/ruby/2.4.0/gems/actionpack-4.2.10/lib/action_controller/metal/redirecting.rb" line 91 in _compute_redirect_to_location
2
File "/app/vendor/bundle/ruby/2.4.0/gems/turbolinks-2.5.3/lib/turbolinks/xhr_headers.rb" line 21 in _compute_redirect_to_location
3
File "/app/vendor/bundle/ruby/2.4.0/gems/actionpack-4.2.10/lib/action_controller/metal/redirecting.rb" line 75 in redirect_to
4
File "/app/vendor/bundle/ruby/2.4.0/gems/actionpack-4.2.10/lib/action_controller/metal/flash.rb" line 57 in redirect_to
5
File "/app/vendor/bundle/ruby/2.4.0/gems/actionpack-4.2.10/lib/action_controller/metal/instrumentation.rb" line 64 in block in redirect_to
6
File "/app/vendor/bundle/ruby/2.4.0/gems/activesupport-4.2.10/lib/active_support/notifications.rb" line 164 in block in instrument
7
File "/app/vendor/bundle/ruby/2.4.0/gems/activesupport-4.2.10/lib/active_support/notifications/instrumenter.rb" line 20 in instrument
8
File "/app/vendor/bundle/ruby/2.4.0/gems/activesupport-4.2.10/lib/active_support/notifications.rb" line 164 in instrument
9
File "/app/vendor/bundle/ruby/2.4.0/gems/actionpack-4.2.10/lib/action_controller/metal/instrumentation.rb" line 63 in redirect_to
10
File "/app/app/controllers/concerns/invitation_controller_concerns.rb", line 53 in reject

To do 📋

• Claim this issue (comment below, or assign yourself if you are part of the codebar org)
• Fork and clone the repository
• Update the relevant files. Follow the steps to fix section in this issue.
• Commit your changes as one commit. Use the title of this issue as your commit message
• Submit a pull request, make sure you mention #codebar24PR2017 in the description
• Mention this issue in the PR description by including it's number
• Have your pull request reviewed & merged by a codebar team member