Editor for spreadsheet import schema

[kellpossible]

It would be good to store the spreadsheet schema in the database and allow admins/users of the system to update them or create new ones for new types of spreadsheets.

Options:

• https://github.com/json-editor/json-editor (has a bunch of nice javascript extensions too) could also be used to rapidly prototype the forecast form perhaps.
• https://github.com/josdejong/jsoneditor
• https://ace.c9.io/ with the https://packagecontrol.io/packages/RON compiled to a .tmlanguage file.