Add web mentions

spec/adamantium/unit/link_finder_spec.rb

@@ -0,0 +1,11 @@
+require "spec_helper"
+
+RSpec.describe Adamantium::LinkFinder do
+  subject { described_class.new }
+
+  it "finds allowed links in a string" do
+    text = "Check out some of these cool websites: https://google.com https://example.com or even http://twitter.com and https://pinboard.in!"
+
+    expect(subject.call(text)).to eq ["https://example.com", "https://pinboard.in"]
+  end
+end