Use more descriptive method nameing

lib/mutant/cli.rb

@@ -193,7 +193,7 @@ module Mutant
     #
     def parse_matchers(patterns)
       patterns.each do |pattern|
-        matcher = Classifier.build(@cache, pattern)
+        matcher = Classifier.run(@cache, pattern)
         @matchers << matcher if matcher
       end
     end

lib/mutant/cli/classifier.rb

@@ -65,7 +65,7 @@ module Mutant
       #
       # @api private
       #
-      def self.build(cache, pattern)
+      def self.run(cache, pattern)
         matches = find(pattern)
         case matches.length
         when 0