Configuration to file path for attachment

[jonstorer]

DO NOT MERGE THIS

this won't pass on travis until the tungus issues are cleared up

I plan on cleaning this up a lot before it's ready to merge. But please provide as much feedback as you can. Thanks!
#10

This is working. However, I had issues with Tungus.

This change sets target on the attachment. When then attachment is passed to the storageProvider, the provider can use it or ignore it.

target is set 3 ways.

// default
// :modelName/:fieldName/:id

schema.plugin(crate, {
  storage: new Storage(),
  fields: { file: { } }
})

// options for the model
// url:

schema.plugin(crate, {
  url: ':modelName/files/:updated_at/:id'
  storage: new Storage(),
  fields: { file: { } }
})

// per attachment
// url:

schema.plugin(crate, {
  storage: new Storage(),
  fields: {
    file: {
      url: ':collectionName/:id-:updated_at'
    }
  }
})

Todo

• update README
• provide examples

[jonstorer]

I'm using this here instead of model, because model can sometimes be something other than a model for array type fields.

[jonstorer]

4 - 28, seems complicated, but it makes 40-43 simple. Any refactoring suggestions?

[jonstorer]

check out this awesome storage provider using the target property!

[achingbrain]

Thanks for this - looks like you're putting a ton of work in. I'm away from the computer for a few days - I'll take an in depth look when I get back.

[achingbrain]

Be careful with your casing - the new file is TargetBuilder but you are importing targetBuilder which will work on case-insensitive file systems (e.g. Windows, Mac OS X) but fail on case sensitive ones (e.g. most Linux file systems)

[jonstorer]

My bad, missed that in refactoring. In the first pass, targetBuilder was a constructor.

[jonstorer]

@achingbrain I simplified the target builder.