Rakefile in abstract_interface-0.1.5 vs Rakefile in abstract_interface-0.1.6

@@ -1,10 +1,11 @@
 require 'rake_ext'
 
 gem_spec(
   :name => "abstract_interface",
-  :version => "0.1.5",
+  :version => "0.1.6",
   :summary => "Abstract Interface for the Crystal Framework",
+  :dependencies => %w(crystal),
 
   :author => "Alexey Petrushin",
   :homepage => "http://github.com/alexeypetrushin/abstract_interface"
 )
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