add default user signatures

app/javascript/application.js

@@ -17,6 +17,7 @@ import SetTimezone from './elements/set_timezone'
 import AutoresizeTextarea from './elements/autoresize_textarea'
 import SubmittersAutocomplete from './elements/submitter_autocomplete'
 import FolderAutocomplete from './elements/folder_autocomplete'
+import SignatureForm from './elements/signature_form'
 
 import * as TurboInstantClick from './lib/turbo_instant_click'
 
@@ -47,6 +48,7 @@ window.customElements.define('set-timezone', SetTimezone)
 window.customElements.define('autoresize-textarea', AutoresizeTextarea)
 window.customElements.define('submitters-autocomplete', SubmittersAutocomplete)
 window.customElements.define('folder-autocomplete', FolderAutocomplete)
+window.customElements.define('signature-form', SignatureForm)
 
 document.addEventListener('turbo:before-fetch-request', encodeMethodIntoRequestBody)
 document.addEventListener('turbo:submit-end', async (event) => {