Ignore Gemfile.lock

Gemfile.lock it's not really needed in the repo. Get rid of it.

Signed-off-by: Emanuele <feliziani.emanuele@gmail.com>
Change the POST url

The POST url has been changed from save-position to save-coords.

Signed-off-by: Emanuele <feliziani.emanuele@gmail.com>
Setup DataMapper

Setup DataMapper and a simple model named Coords. I still have to decide how to treat the database, but at this stage I just have to check that everything is working correctly.

Signed-off-by: Emanuele <feliziani.emanuele@gmail.com>