Ruby

Rails 5.0.0.beta1.1, 4.2.5.1, 4.1.14.1, 3.2.22.1, and rails-html-sanitizer 1.0.3 have been released!, Rails Dynamic Render to RCE (CVE-2016-0752) и Caching in development environment in Rails 5
Chris Seaton on Massively Improving Ruby Performance with JRuby+Truffle и Stubbing External Services in Rails
Ruby Marshalling from A to Z и Ruby Private Class Methods
Replacing Pingdom with Ruby and Heroku и Increment_with_sql — provides increment_with_sql! and decrement_with_sql! for ActiveRecord models

JavaScript

V8 Release 4.9, Understanding Garbage Collection and hunting Memory Leaks in Node.js и Parse alternatives
The Controversial State of JavaScript Tooling и Angular 2 is ugly!
Discontinuing IE 8 Support in React DOM, What we learnt from testing Searchkit’s React Components и Babel Handbook
Awesome Marionette.js, MediumEditor — a lightweight inline text editor inspired by the editor from the Medium blogging platform, Hint.css — a pure CSS tooltip library for your lovely websites и Voxel.css makes 3D rendering easy