用户组织图片不存在时处理

app/views/organizations/organizations/_detail.json.jbuilder

@@ -10,7 +10,7 @@ json.max_repo_creation organization.max_repo_creation
 json.num_projects organization.num_projects
 json.num_users organization.num_users
 json.num_teams organization.num_teams
-json.avatar_url url_to_avatar(organization)
+json.avatar_url url_to_avatar(organization).blank?? User::Avatar.get_letter_avatar_url(organization.login) : url_to_avatar(organization)
 json.created_at organization.created_on.strftime("%Y-%m-%d")
 json.news_banner_id organization.news_banner_id
 json.news_content organization.news_content

app/views/projects/banner_recommend.json.jbuilder

@@ -11,7 +11,7 @@ json.projects do
       json.name owner.try(:show_real_name)
       json.type owner.type
       json.login owner.login
-      json.image_url url_to_avatar(owner)
+      json.image_url url_to_avatar(owner).blank?? User::Avatar.get_letter_avatar_url(owner.login) : url_to_avatar(owner)
     end
   
     json.category do

app/views/projects/index.json.jbuilder

@@ -30,7 +30,7 @@ json.projects @projects do |project|
       json.type user.type
       json.name user.try(:show_real_name)
       json.login user.login
-      json.image_url url_to_avatar(user)
+      json.image_url url_to_avatar(user).blank?? User::Avatar.get_letter_avatar_url(user.login) : url_to_avatar(user)
     end
   end