Add credits to a few curricula ✨

For the JS curricula, Learn to Code, and the Rails job board & message board curricula,
add a note to the last page of the curriculum with the name of the original author and a link to the history of the curriculum
on GitHub so that curious people can see who has contributed specifically to this curriculum.

I'm using the directory history instead of the contribution graph because the contribution graph can't be
broken down by what part of the codebase the contribution was made to, as far as I can tell.

Author: lilliealbert

sites/en/javascript-snake-game/lesson-14.step

@@ -1 +1,10 @@
 insert '../javascript-to-do-list/_deploying_your_site'
+
+message <<-MARKDOWN
+# Credits
+
+This curriculum was originally written by
+[Zassmin Montes de Oca](http://zassmin.com/) and
+[Zee Spencer](http://www.zeespencer.com/),
+and has been improved by all sorts of [lovely RailsBridge volunteers](https://github.com/railsbridge/docs/commits/master/sites/en/javascript-snake-game).
+MARKDOWN

sites/en/javascript-to-do-list-with-react/next_steps.step

@@ -20,3 +20,11 @@ ul do
     a "http://railsbridge.org/learn/resources", href: "http://railsbridge.org/learn/resources"
   end
 end
+
+message <<-MARKDOWN
+# Credits
+
+This curriculum was originally written by
+[Srinivas Rao](https://twitter.com/raorao_)
+and has been improved by all sorts of [lovely RailsBridge volunteers](https://github.com/railsbridge/docs/commits/master/sites/en/javascript-to-do-list-with-react).
+MARKDOWN

sites/en/javascript-to-do-list/next_steps.step

@@ -20,3 +20,11 @@ ul do
     a "http://railsbridge.org/learn/resources", href: "http://railsbridge.org/learn/resources"
   end
 end
+
+message <<-MARKDOWN
+# Credits
+
+This curriculum was originally written by
+[Srinivas Rao](https://twitter.com/raorao_)
+and has been improved by all sorts of [lovely RailsBridge volunteers](https://github.com/railsbridge/docs/commits/master/sites/en/javascript-to-do-list).
+MARKDOWN

sites/en/job-board/add_more_things.step

@@ -15,4 +15,8 @@ message <<-MARKDOWN
   * Add a user model and auth with Devise
   * Test it! Write a controller spec.
 
+  ## Credits
+
+  This curriculum was originally written by [Lillie Chilen](http://www.twitter.com/lilliealbert)
+  and has been improved by all sorts of [lovely RailsBridge volunteers](https://github.com/railsbridge/docs/commits/master/sites/en/job-board).
 MARKDOWN

sites/en/learn-to-code/next_steps.md

@@ -14,6 +14,8 @@
 
 # Thanks
 
-* to all the TAs
+* to all the TAs!
 * to all the students!
+* to [Alex Chaffee](http://alexchaffee.com/), the original author of this curriculum, and
+* to all the [RailsBridge volunteers](https://github.com/railsbridge/docs/commits/master/sites/en/learn-to-code) who have helped make it better!
 

sites/en/message-board/add_other_features_of_your_choosing.step

@@ -13,4 +13,11 @@ Suggestions:
 * Deploy to Heroku and send your message board to all your friends!
 
 ## ...and that's that! Good luck! Make more things! Come back again!
+
+# Credits
+
+This curriculum was originally written by
+[Lillie Chilen](http://www.twitter.com/lilliealbert) and
+[Travis Grathwell](https://github.com/tjgrathwell),
+and has been improved by all sorts of [lovely RailsBridge volunteers](https://github.com/railsbridge/docs/commits/master/sites/en/message-board).
 MARKDOWN