First steps for pagination

Pagination working with a link for the next page.
Removed unnecessary adapter
Merge branch 'wip/ember_migration'
Merge branch 'feat/pagination'
Merge branch 'master' of https://github.com/AEHO/traintool into AEHO-master
Readded the main adapter
Exercises list with "load more" button

Added a button to collect more exercises from the backend
in place of the paginations scheme.
Merge pull request #46 from MateusZitelli/feat/infinite_scroll

Load more exercises from backend functionality added