# Symbols
ages = Hash[:Nnamdi => 17,:Tolu => 18] #{:Nnamdi=>17, :Tolu=>18}

# Let's sprinkle some Sugar on it eyy..
ages = Hash[Nnamdi: 17, Tolu: 18] # => {:Nnamdi=>17, :Tolu=>18}

# User class
class User
  def initialize username, password
    @username = username
    @password = password
  end
end

usr1 = User.new :Tolu, :trees345 # => #<User:0x000000018b5578 @username=:Tolu, @password=:trees345>
usr2 = User.new :Jake, :trees567 # => #<User:0x000000018d41d0 @username=:Jake, @password=:trees567>

# Objects
user_to_user = Hash[usr2 => usr1]
# =>{ #<User:0x000000018d41d0 @username=:Jake, @password=:trees567>=>#<User:0x000000018b5578 @username=:Tolu, @password=:trees345>}

# Even Arrays
users = [] # => []

# shove it up its ...
users << usr1 # => [#<User:0x000000018b5578 @username=:Tolu, @password=:trees345>]
users << usr2 # => [#<User:0x000000018b5578 @username=:Tolu, @password=:trees345>, #<User:0x000000018d41d0 @username=:Jake, @password=:trees567>]

# see
ages = {users => 17}
 => {[#<User:0x000000018b5578 @username=:Tolu, @password=:trees345>, #<User:0x000000018d41d0 @username=:Jake, @password=:trees567>]=>17}