Updated Composer field to a multi-select dropdown to contain multiple composer names.

[aidansakata]

Pull Request Template

Description

I saw the issue posted by gorgobacka for the multiple artists for one song. I modified the composer field from an empty string to an empty array to store multiple composer names and created a multi-select dropdown. I then modified the handleChange and requestData functions in UploadPage.js to accept an array of strings. I then modified the uploadSheets and updateSheets functions in dataActions.js to support these changes. I added the function GetComposerAsSlice in upload.go so that the uploadRequest struct can split the composer string at the comma and space delimiter and return a slice of the composers' names.

Fixes # (issue)

Fixes the issue posted by gorgobacka (#12).

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have checked my code and corrected any misspellings

[vallezw]

Hey @aidansakata nice feature! Could you perhaps show a demo video in this thread on how it looks like? Makes it easier to review