1. 在管理员用户表中增加avatar_path列
bundle exec rails generate migration add_avatar_path_to_users

add_column :users, :avatar_path, :string, comment: '头像路径'

resources :users do
    collection do
         get :show_profile
         get :edit_profile
         post :save_profile
    end

end

  def show_profile
      if session[:current_user].blank?
         redirect_to '/articles' and return
      end
        @user = User.find session[:current_user]['id']
    end
   
    def edit_profile
      if session[:current_user].blank?
          redirect_to '/articles' and return
      end
    end
 
    def save_profile
       if session[:current_user].blank?
        redirect_to '/articles' and return
    end
 
       uploaded_io = params[:avatar_image]
        file_name = Rails.root.join('public', 'images', uploaded_io.original_filename)
        File.open(file_name, 'wb') do |file|
        file.write(uploaded_io.read)
     end
 
      user = User.find session[:current_user]['id']
      user.avatar_path = '/images/' +  uploaded_io.original_filename
      user.save!
 
     redirect_to '/users/show_profile'
end

      <h1>个人档案</h1>
      <p>我的头像
         <%= link_to '编辑', 'edit_profile', style: 'margin-left: 20px; text-decoration: none;' %>
     </p>
     <%= @user.avatar_path %><br/>
     <img src="<%= @user.avatar_path %>", style='width: 200px; height: 200px; margin-top: 20px;' />

 <h1>编辑个人档案页面</h1>
     <p>我的头像
        <%= link_to '返回', show_profile_users_path, style: 'margin-left: 20px; text-decoration: none;'%>
     </p>
       <%= form_tag '/users/save_profile', multipart: true do %>
       <%= file_field_tag "avatar_image" %>
       <%= submit_tag "提交" %>
   <% end %>