feature: issue #57 Select multiple skills on job creation

src/page-job-offer-create.pug

@@ -4,8 +4,10 @@ div
   .form-view
     sib-form.block(
       data-src=`${sdn}/job-offers/`,
-      data-fields="title, description, skills",
+      data-fields='author, title, description, skills',
       widget-author='sib-form-dropdown',
       range-skills= `${sdn}/skills/`,
+      range-author= `${sdn}/users/`,
+      widget-skills='sib-form-multiple-dropdown'
       next="job-offers"
     )