Added UserTeam core models (team and m-t-m relationships) and updated other models

app/models/user_team_user_relationship.rb

@@ -0,0 +1,15 @@
+class UserTeamUserRelationship < ActiveRecord::Base
+  attr_accessible :group_admin, :permission, :user_id, :user_team_id
+
+  belongs_to :user_team
+  belongs_to :user
+
+  validates :user_team, presence: true
+  validates :user,      presence: true
+
+  scope :with_user, ->(user) { where(user_id: user.id) }
+
+  def user_name
+    user.name
+  end
+end