README.md in eulim-0.0.3 vs README.md in eulim-0.0.4

@@ -29,21 +29,24 @@
 * Element
 * Compound
 
 #### Element
 
-* H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg
+* H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K , Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni
 * symbol, name, atomic_number, atomic_mass
 
+#### Compound
+
 ## Usage
 
 	$ Eulim::Chemistry::Element.get_by_symbol("H")
 	=> #<Eulim::Chemistry::Element:0x0055ac58c146e8 @symbol="Mg", @name="Magnesium", @atomic_number=12, @atomic_mass=24.305>
 
 	$ Eulim::Chemistry::Element.get_by_atomic_number(12)
 	=> #<Eulim::Chemistry::Element:0x0055ac58c146e8 @symbol="Mg", @name="Magnesium", @atomic_number=12, @atomic_mass=24.305>
 
-
+	$ Eulim::Chemistry::Compound.constituent_elements("CaCO3")
+	=> [#<Eulim::Chemistry::Element:0x0055c971365598 @symbol="Ca", @name="Calcium", @atomic_number=20, @atomic_mass=40.078>, #<Eulim::Chemistry::Element:0x0055c9713652c8 @symbol="C", @name="Carbon", @atomic_number=6, @atomic_mass=12.0107>, #<Eulim::Chemistry::Element:0x0055c971365048 @symbol="O", @name="Oxygen", @atomic_number=8, @atomic_mass=15.9996>]
 ## Development
 
 After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
 
 To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).