add creature and base rp_world

app/models/wow_creature.rb

@@ -0,0 +1,10 @@
+class WowCreature < ApplicationRecord
+  extend Mobility
+  translates :name
+
+  belongs_to :wow_creature_family, optional: true
+  belongs_to :wow_creature_type, optional: true
+
+  validates :name, presence: true
+  validates :creature_id, presence: true, uniqueness: true
+end