Add categories in typeahead

Separe the exercises suggestions by those created by the users and the
defaults from the gymup.
Add .gitignore

Add new .gitignore and ignore node_modules folder.
Merge branch 'feat/server-config' into feat/exercise-typeahead
Change the URL to retrive the suggestions

Change the URL to get the exercises suggestions to follow #78.
Add analytics script

Add in the index.html the analytics script.