Handle blank lines and comments in procfiles (#9)

spec/nox/procfile_spec.cr

@@ -17,5 +17,23 @@ Spectator.describe Nox::Procfile do
         procfile_entry("frontend", "yarn start")
       )
     end
+
+    it "handles spaces and comments in various places" do
+      content = <<-PROCFILE
+
+      web: crystal src/app.cr
+
+      # comment!
+      frontend: yarn start
+
+      PROCFILE
+
+      result = Nox::Procfile.parse(content)
+
+      expect(result.entries).to contain_exactly(
+        procfile_entry("web", "crystal src/app.cr"),
+        procfile_entry("frontend", "yarn start")
+      )
+    end
   end
 end

src/nox/procfile.cr

@@ -8,7 +8,9 @@ struct Nox::Procfile
   def self.parse(content : String) : self
     proc_file = new
     content.each_line do |line|
-      match_data = ENTRY_REGEX.match(line).not_nil!
+      match_data = ENTRY_REGEX.match(line)
+      next if match_data.nil?
+
       proc_file.entries << Nox::Procfile::Entry.new(match_data[1], match_data[2])
     end
     proc_file