init commit

app/models/ability.rb

@@ -0,0 +1,34 @@
+class Ability
+  def self.allowed(object, subject)
+    case subject.class.name
+    when "Project" then project_abilities(object, subject)
+    else []
+    end
+  end
+
+  def self.project_abilities(user, project)
+    rules = []
+
+    rules << [
+      :read_project,
+      :read_issue,
+      :read_team_member,
+      :read_note 
+    ] if project.readers.include?(user)
+
+    rules << [
+      :write_project,
+      :write_issue,
+      :write_note 
+    ] if project.writers.include?(user)
+
+    rules << [
+      :admin_project,
+      :admin_issue,
+      :admin_team_member,
+      :admin_note 
+    ] if project.admins.include?(user)
+
+    rules.flatten
+  end
+end