Abilities refactoring

app/models/ability.rb

@@ -19,7 +19,7 @@ class Ability
       :read_team_member,
       :read_merge_request,
       :read_note
-    ] if project.readers.include?(user)
+    ] if project.allow_read_for?(user)
 
     rules << [
       :write_project,
@@ -27,16 +27,18 @@ class Ability
       :write_snippet,
       :write_merge_request,
       :write_note
-    ] if project.writers.include?(user)
+    ] if project.allow_write_for?(user)
 
     rules << [
+      :modify_issue,
+      :modify_snippet,
       :admin_project,
       :admin_issue,
       :admin_snippet,
       :admin_team_member,
       :admin_merge_request,
       :admin_note
-    ] if project.admins.include?(user)
+    ] if project.allow_admin_for?(user)
 
     rules.flatten
   end
@@ -48,6 +50,7 @@ class Ability
           [
             :"read_#{name}",
             :"write_#{name}",
+            :"modify_#{name}",
             :"admin_#{name}"
           ]
         else

app/models/project.rb

@@ -161,6 +161,18 @@ class Project < ActiveRecord::Base
     @admins ||= users_projects.includes(:user).where(:project_access => PROJECT_RWA).map(&:user)
   end
 
+  def allow_read_for?(user)
+    !users_projects.where(:user_id => user.id, :project_access => [PROJECT_R, PROJECT_RW, PROJECT_RWA]).empty?
+  end
+
+  def allow_write_for?(user)
+    !users_projects.where(:user_id => user.id, :project_access => [PROJECT_RW, PROJECT_RWA]).empty?
+  end
+
+  def allow_admin_for?(user)
+    !users_projects.where(:user_id => user.id, :project_access => [PROJECT_RWA]).empty? || owner_id == user.id
+  end
+
   def root_ref 
     default_branch || "master"
   end