Describe the bug

Attempted to import my TeslaFI export. It failed with:

teslamate_1  | 06:39:51.377 [info] Importing 11 file(s) ...
teslamate_1  | 06:39:51.383 [error] GenStateMachine TeslaMate.Import terminating
teslamate_1  | ** (FunctionClauseError) no function clause matching in CSV.Decoding.Preprocessing.Lines.starts_sequence?/5
teslamate_1  |     (csv 2.3.1) CSV.Decoding.Pr

With the recent release of Phoenix 1.5 🎉 https://elixirforum.com/t/phoenix-v1-5-0-released/30693
Now is a great time to go through this example/tutorial with a fresh pair of eyes and completely update it (including) links to code snapshots. We can also extend it to include auth_plug #25 🔐 and presence #32 🚀.

• Checkout master
• Create new branch e.g: `update-t

Would be nice to improve the docs, make it clearer, simpler and easy to understand.

I would like to be able to search multiple indices. I suggest the search function is extended so that the index parameter can be an array.