```ruby
ActiveAdmin.register User do
  actions :index, :edit, :update
  filter :name
  filter :email

  index :download_links => false do
    column :name
    column :email
    column "Invitation Link" do |user|
      if user.invitation_token
        link_to "Invite link (#{user.invitation_token})",
          accept_invitation_url(user, :invitation_token => user.invitation_token)
      end
    end
    column :created_at
    column :last_sign_in_at
    column :is_admin
    column "No. of groups", :memberships_count
    default_actions
  end

  form do |f|
    f.inputs "Details" do
      f.input :name
      f.input :email
      f.input :username
      f.input :is_admin
    end
    f.buttons
  end

  member_action :update, :method => :put do
    user = User.find(params[:id])
    user.name = params[:user][:name]
    user.email = params[:user][:email]
    user.username = params[:user][:username]
    user.is_admin = params[:user][:is_admin]
    user.save
    redirect_to admin_users_url, :notice => "User updated"
  end
end
```

Remove invitation link from admin user list
user
```ruby
ActiveAdmin.register User do
  actions :index, :edit, :update
  filter :name
  filter :email

  index :download_links => false do
    column :name
    column :email
    column :created_at
    column :last_sign_in_at
    column :is_admin
    column "No. of groups", :memberships_count
    default_actions
  end

  form do |f|
    f.inputs "Details" do
      f.input :name
      f.input :email
      f.input :username
      f.input :is_admin
    end
    f.buttons
  end

  member_action :update, :method => :put do
    user = User.find(params[:id])
    user.name = params[:user][:name]
    user.email = params[:user][:email]
    user.username = params[:user][:username]
    user.is_admin = params[:user][:is_admin]
    user.save
    redirect_to admin_users_url, :notice => "User updated"
  end
end
```
assistant