app/overrides/spree/admin/users/index.rb
Deface::Override.new(
:virtual_path => "spree/admin/users/index",
:name => "referral_code_header",
:insert_before => "[data-hook='admin_users_index_headers'] th:nth-child(2)",
:text => "<th class='align-center'>Referrals</th>"
)
Deface::Override.new(
:virtual_path => "spree/admin/users/index",
:name => "referral_code",
:insert_before => "[data-hook='admin_users_index_rows'] td:nth-child(2)",
:text => "<td class='align-center'><%= user.referred_count %></td>"
)
Deface::Override.new(
:virtual_path => "spree/admin/users/index",
:name => "column_withds",
:replace => "#listing_users > colgroup",
:text => "<col style='width: 75%'><col style='width: 10%'><col style='width: 15%'>"
)