User email to send message

This is a (most likely) temporary solution to messaging in the app. Here we simply use mailto: to open an email client on their phone/computer to send an email to get the ingredient. Some info is auto-filled.

I made a change in the user schema to accommodate this change. To update your dev database, go into psql and run:
> alter table "Users" add column email varchar(255);

I will make this change in the production database.