Add medium icon

#85

Author: mincong-h

_config.yml

@@ -48,7 +48,7 @@ author:
   weibo     : # "user_id"   the last part of your profile url, e.g. https://www.weibo.com/user_id/profile?...
   googleplus: # "user_id"   the last part of your profile url, e.g. https://plus.google.com/u/0/user_id
   telegram  : # "user_name" the last part of your profile url, e.g. https://t.me/user_name
-  medium    : # "user_name" the last part of your profile url, e.g. https://medium.com/user_name
+  medium    : '@mincong' # "user_name" the last part of your profile url, e.g. https://medium.com/user_name
   zhihu     : # "user_name" the last part of your profile url, e.g. https://www.zhihu.com/people/user_name
   douban    : # "user_name" the last part of your profile url, e.g. https://www.douban.com/people/user_name
   linkedin  : mincong-huang  # "user_name" the last part of your profile url, e.g. https://www.linkedin.com/in/user_name