Remove markdown rule

Will re-add in a jiffy.

Author: CalebFenton

db/seeds.rb

@@ -23,12 +23,6 @@
     value: '(?i)(advisory|attack|(un)?authoriz(e|ation)|clickjack|cross.site|csrf|\bCVE\b|deadlock|denial.of.service|\bEOP\b|exploit|hijack|infinite.loop|malicious|\bNVD\b|OSVDB|\bRCE\b|\bReDoS\b|remote.code.execution|security|victim|\bvuln|\bXEE\b|\bXSRF\b|\bXSS\b|\bXXE\b)',
     description: 'Strong indication of a silent vulnerability fix'
   },
-  {
-    name: 'markdown_file',
-    rule_type_id: 1,
-    value: '(?i)\.(md|markdown)\z',
-    description: 'Markdown file'
-  },
   {
     name: 'non_code_file',
     rule_type_id: 1,
@@ -47,7 +41,6 @@
     value: '(?i)(abuse|compliant|constant.time|credential|\bcrypto|escalate|exhaustion|forced|infinite|RFC\d{4,5})',
     description: 'Weak indication of a silent vulnerability fix'
   },
-
   {
     name: 'npm_authentication_file',
     rule_type_id: 1,