added geocoding

app/models/supporter.rb

@@ -1,6 +1,10 @@
 class Supporter
   include Mongoid::Document
   include Mongoid::Timestamps
+  include Geocoder::Model::Mongoid
+
+  geocoded_by :address
+  after_validation :geocode          # auto-fetch coordinates
 
   field :first_name,   type: String
   field :last_name,    type: String
@@ -10,6 +14,7 @@ class Supporter
   field :email,        type: String
   field :support,      type: String # Indicates the type of support
   field :age_category, type: String
+  field :coordinates,  type: Array
 
   validates :first_name,   presence: true
   validates :last_name,    presence: true
@@ -19,4 +24,8 @@ class Supporter
   validates :email,        presence: true, uniqueness: true
   validates :support,      presence: true
   validates :age_category, presence: true
+
+  def address
+    "#{street}, #{zip}, #{city}, Switzerland"
+  end
 end