Configure undercover to exclude files

.simplecov

@@ -2,10 +2,17 @@
 # frozen_string_literal: true
 
 SimpleCov.start 'rails' do
+  # The rails profile contains some filters already:
+  #
+  # - "/test/"
+  # - "/features/"
+  # - "/spec/"
+  # - "/autotest/"
+  # - /^\/config\//
+  # - /^\/db\//
   add_filter '/bin/'
-  add_filter '/config/'
+  add_filter '/config/' # to include engine config
   add_filter '/script'
-  add_filter '/db'
 
   formatter SimpleCov::Formatter::SimpleFormatter
 end

.undercover

@@ -1,4 +1,9 @@
 #!/bin/env ruby
 # frozen_string_literal: true
 
--c master
+--compare master
+
+# This shouldn't be needed in undercover > 0.7.4
+#
+# * https://github.com/grodowski/undercover/issues/233
+--exclude-files "bin/*,db/*,config/*,spec/*,engines/*/config/*,engines/*/spec/*"