Add `Integer.try_convert`

Again

README.md

@@ -129,6 +129,10 @@ itself, JRuby and Rubinius.
 
 - `dirname` (with depth argument)
 
+#### Integer
+
+- `try_convert`
+
 #### MatchData
 
 - `match`

lib/backports/3.1.0/integer.rb

@@ -0,0 +1,3 @@
+require 'backports/tools/require_relative_dir'
+
+Backports.require_relative_dir

lib/backports/3.1.0/integer/try_convert.rb

@@ -0,0 +1,7 @@
+class Integer
+  require 'backports/tools/arguments'
+
+  def self.try_convert(obj)
+    ::Backports.try_convert(obj, ::Integer, :to_int)
+  end
+end unless Integer.respond_to? :try_convert