Add Disassemble Some Codes as a ruby til.

ruby/disassemble-some-codes.md

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+# Disassemble Some Codes
+
+The
+[`RubyVM::InstructionSequence`](http://ruby-doc.org/core-2.2.0/RubyVM/InstructionSequence.html)
+class makes it easy to compile, disassemble, and inspect bits of Ruby code.
+We can quickly take a peek under the hood at a simple ruby statement, such
+as `a = 1 + 2`, like so:
+
+```ruby
+> ruby_code = 'a = 1 + 2'
+=> a = 1 + 2
+> compiled_code = RubyVM::InstructionSequence.compile(ruby_code)
+=> <RubyVM::InstructionSequence:<compiled>@<compiled>>
+> puts compiled_code.disasm
+== disasm: <RubyVM::InstructionSequence:<compiled>@<compiled>>==========
+local table (size: 2, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, kw:
+-1@-1, kwrest: -1])
+[ 2] a
+0000 trace            1                                               (   1)
+0002 putobject_OP_INT2FIX_O_1_C_
+0003 putobject        2
+0005 opt_plus         <callinfo!mid:+, argc:1, ARGS_SIMPLE>
+0007 dup
+0008 setlocal_OP__WC__0 2
+0010 leave
+=> nil
+```
+
+It is a bit archaic, but when we get to the line starting with `0002`, we
+see values (`1` and then `2`) pushed onto the stack, then operated on, and
+finally set on the local variable `a`. Fun!