:bug: accounting for sortname

vue-theme/src/store/modules/artist.js

     artistsList.forEach((artist, i) => {
         const lastWord = artist.slug.split('-').filter(c => c).pop()
         const firstCharaOfLastWord = lastWord[0]
-        
+        const firstCharaOfSortWord = artist.sortname[0]
+        const charaIndex = alphabet.indexOf(firstCharaOfLastWord) < alphabet.indexOf(firstCharaOfSortWord) ? alphabet.indexOf(firstCharaOfLastWord) : alphabet.indexOf(firstCharaOfSortWord)
         // The first artist you've seen in this batch
         if(i == 0) {
-            seen = alphabet.indexOf(firstCharaOfLastWord)
+            seen = charaIndex
             console.log(alphabet[seen], seen)
             flatPacked.push({ slug: alphabet[seen], title: alphabet[seen], inbetween: true })
         }
 
-        if (alphabet.indexOf(firstCharaOfLastWord) == seen + 1) {
+        if (charaIndex == seen + 1) {
             seen++
             flatPacked.push({ slug: alphabet[seen], title: alphabet[seen], inbetween: true })
         }