Add validation to text embed key

spec/args/embed_key_spec.rb

@@ -0,0 +1,13 @@
+require 'spec_helper'
+require 'squib/args/embed_key'
+
+describe Squib::Args::EmbedKey do
+
+  context '#validate_key' do
+
+    it 'converts to string' do
+      expect(subject.validate_key(2.5)).to eq ('2.5')
+    end
+
+  end
+end