Adds separate route entries for story, revision, practice (#10220)
Adds separate route entries for story, revision, practice (#10220)

Using regex definition seems to introduce an issue when the URL ends with /. E.g. /learn/math/fractions/story/ should ideally redirect to /learn/math/fractions/story (notice the / in the end is removed). This is expected to happen automatically because strict_slash param is set to True in main.get_redirect_route. However, this does not respect routes defined as regex, causing issues in navigation. As a fix, these URLs are separated out into individual route definitions.
kevinlee12/oppia,prasanna08/oppia,kevinlee12/oppia,oppia/oppia,oppia/oppia,brianrodri/oppia,prasanna08/oppia,brianrodri/oppia,brianrodri/oppia,kevinlee12/oppia,kevinlee12/oppia,oppia/oppia,oppia/oppia,oppia/oppia,brianrodri/oppia,prasanna08/oppia,prasanna08/oppia,kevinlee12/oppia,brianrodri/oppia,prasanna08/oppia