Update markdown files

- Update README
- Add Code of Conduct
- Bump license year

CODE_OF_CONDUCT.md

@@ -0,0 +1,76 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, sex characteristics, gender identity and expression,
+level of experience, education, socio-economic status, nationality, personal
+appearance, race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or
+  advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+  address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies within all project spaces, and it also applies when
+an individual is representing the project or its community in public spaces.
+Examples of representing a project or community include using an official
+project e-mail address, posting via an official social media account, or acting
+as an appointed representative at an online or offline event. Representation of
+a project may be further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at [hello@ruby2d.com](mailto:hello@ruby2d.com). All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
+
+[homepage]: https://www.contributor-covenant.org
+
+For answers to common questions about this code of conduct, see
+https://www.contributor-covenant.org/faq

LICENSE.md

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright © 2018 Tom Black ([blacktm.com](http://www.blacktm.com))
+Copyright © 2019 Tom Black ([blacktm.com](http://www.blacktm.com))
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 

README.md

@@ -1,6 +1,6 @@
 # Welcome to Ruby 2D!
 
-[![Gem](https://img.shields.io/gem/v/ruby2d.svg)](https://rubygems.org/gems/ruby2d) [![Build Status](https://travis-ci.com/ruby2d/ruby2d.svg?branch=master)](https://travis-ci.com/ruby2d/ruby2d) [![Gitter](https://badges.gitter.im/ruby2d/ruby2d.svg)](https://gitter.im/ruby2d/ruby2d)
+![Gem](https://img.shields.io/gem/v/ruby2d.svg?color=%23f63c38&style=for-the-badge) ![Build Status](https://img.shields.io/travis/com/ruby2d/ruby2d.svg?style=for-the-badge) ![Gitter](https://img.shields.io/gitter/room/ruby2d/ruby2d.svg?color=%23ff0064&style=for-the-badge)
 
 This is the [Ruby 2D gem](https://rubygems.org/gems/ruby2d). Check out the [Ruby 2D website](http://www.ruby2d.com) to learn how to get started building 2D apps in Ruby.
 
@@ -24,7 +24,7 @@ Update these submodules at any time using `git submodule update --remote` or the
 Next, install dependencies:
 - With [Bundler](http://bundler.io), run `bundle install` to get the required development gems.
 - Install the native graphics library [Simple 2D](https://github.com/simple2d/simple2d) by following the instructions in its README.
-- Install [MRuby](http://mruby.org) in order to build Ruby 2D apps natively. On macOS using [Homebrew](https://brew.sh), run `brew install mruby`. On Linux, use `sudo apt install mruby libmruby-dev`
+- Install [MRuby](http://mruby.org) in order to build Ruby 2D apps natively. On macOS using [Homebrew](https://brew.sh), run `brew install mruby`. On Ubuntu, use `sudo apt install mruby libmruby-dev`
 
 Finally, run `rake` to build and install the gem locally.
 
@@ -49,33 +49,31 @@ Ruby 2D is an entirely open-source project (including its dependencies) built by
 
 If you'd like to get involved, there are a number of ways to do so:
 
-- **Suggest and implement new features.** 🌟 Ruby 2D is still early in development, so there are plenty of new things it could do. If you have a feature request, or a suggestion on how to improve the domain-specific language, or something else to add, remove, or change, [open a new issue](https://github.com/ruby2d/ruby2d/issues/new) and tell us about it. If you just want to casually talk through an idea without the pressure of opening an issue, send a note to the [mailing list](https://groups.google.com/d/forum/ruby2d) or chat with us on [Gitter](https://gitter.im/ruby2d/ruby2d).
+- **Suggest and implement new features.** 🌟 Ruby 2D already does a lot, but there are plenty of new things it could do. If you have a feature request, or a suggestion on how to improve the domain-specific language, or something else to add, remove, or change, [open a new issue](https://github.com/ruby2d/ruby2d/issues/new) and tell us about it. If you just want to casually talk through an idea without the pressure of opening an issue, send a note to the [mailing list](https://groups.google.com/d/forum/ruby2d) or chat with us on [Gitter](https://gitter.im/ruby2d/ruby2d).
 
-- **Add support for more platforms.** 💻 Ruby 2D aims to be entirely cross platform. Take a look at the [platforms we currently support](http://www.ruby2d.com/platforms) and where the gaps are. Help us test and improve the developer experience on existing platforms and add new ones.
+- **Add support for more platforms.** 💻 Ruby 2D aims to be entirely cross platform. Help us test and improve the developer experience on existing platforms and add new ones.
 
-- **Find and fix issues.** 🐛 Any new project experiencing lots of change will have bugs. Your help identifying and fixing them, and improving performance along the way, will be critical to ensuring others have a solid experience using the library. Check out the [issue tracker](https://github.com/ruby2d/ruby2d/issues) and have at it!
+- **Find and fix issues.** 🐛 Your help identifying and fixing bugs, and improving performance along the way, will be critical to ensuring others have a solid experience using the library. Check out the [issue tracker](https://github.com/ruby2d/ruby2d/issues) and have at it!
 
-- **Write and review documentation.** 📚 Vitally important to the success of every open-source project is documentation. We're off to a decent start here, but there's always more to write and edit. Browse through the [Ruby 2D website](http://www.ruby2d.com) and help us identify areas to add clarity or fill in gaps. At the bottom of every page, you'll see a link to "improve this page" which goes directly to the source file in the [website repo](https://github.com/ruby2d/ruby2d.com), making it easy to suggest changes.
+- **Write and review documentation.** 📚 Vitally important to the success of every open-source project is documentation. We're off to a decent start, but there's always more to write and edit. Browse through the [Ruby 2D website](http://www.ruby2d.com) and help us identify areas to add clarity or fill in gaps. At the top of most pages, you'll see a link to "suggest an edit" which goes directly to the source file in the [website repo](https://github.com/ruby2d/ruby2d.com).
 
-- **Create and improve examples.** 👾 We're currently a little light on sample applications to help folks get started. We'd love to get your ideas on small, single-file apps to guide users through specific features or techniques, which we'll collect in the [examples repository](https://github.com/ruby2d/examples). If you've got larger projects you'd like to highlight, we'd love to hear about them as well! Maybe we can add a gallery page to the website and showcase them... 🤔
+- **Create and improve examples.** 👾 We're currently a little light on sample applications to help folks get started. We'd love to get your ideas for small, single-file apps to guide users through specific features or techniques, which we collect in the [examples repository](https://github.com/ruby2d/examples). [Check out the showcase](http://www.ruby2d.com/showcase) to see what people are building and get some inspiration.
 
 ### Technical contributions
 
-In order to achieve such simplicity, a lot has to happen under the hood. We recommend reviewing Ruby 2D's [technical architecture](http://www.ruby2d.com/learn/tech) for a high-level overview of how everything is put together.
-
-Whether adding a feature or fixing a bug, try to do the following to ensure your pull request gets merged. Some of these might seem daunting, but we're happy to help along the way!
+In order to achieve such simplicity, a lot has to happen under the hood. Whether adding a feature or fixing a bug, try to do the following to ensure your pull request gets merged. Some of these might seem daunting, but we're happy to help along the way!
 
 - **Check if there is an existing issue, and if not, open a new one to start a discussion.** Before dedicating time and energy to an idea or fix, let's make sure it's consistent with the principles and goals of the project, and that we have a solid strategy in place to implement and test.
 
 - **Use a subset of Ruby that works everywhere.** Ruby 2D applications are, of course, written in Ruby. Some users may choose to harness the full power of the language, standard library, and ecosystem of gems by writing interpreted apps targeting the standard implementation, [MRI](https://en.wikipedia.org/wiki/Ruby_MRI). Others may want to target the web via [WebAssembly](https://webassembly.org), mobile devices, or build native desktop applications, all which make use of a different Ruby implementation called [MRuby](http://mruby.org). Ruby 2D aims to support all of these use cases, even with the same app codebase. Your contribution must support a subset of Ruby that is compatible with and behaves similarly across MRI and MRuby. Beyond reading the documentation for each Ruby implementation, you can also try out code snippets on the command line using their respective REPLs: `irb` for MRI, and `mirb` for MRuby.
 
-- **Comprehensively test your change.** Unlike other Ruby libraries, not everything here can be easily covered with unit tests alone. We also need to make sure things look and sound right, inputs work as expected, and behavior is consistent across all [platforms Ruby 2D supports](http://www.ruby2d.com/platforms).
+- **Comprehensively test your change.** Unlike other Ruby libraries, not everything here can be easily covered with unit tests alone. We also need to make sure things look and sound right, inputs work as expected, and behavior is consistent across all platforms Ruby 2D supports.
 
 ## Preparing a release
 
 1. Update the Simple 2D minimum version required in [`extconf.rb`](ext/ruby2d/extconf.rb)
 2. Run tests on all supported platforms
 3. Update the version number in [`version.rb`](lib/ruby2d/version.rb), commit changes
-4. Create a [new release](https://github.com/ruby2d/ruby2d/releases) in GitHub, with tag in the form `v#.#.#`
+4. Create a [new release](https://github.com/ruby2d/ruby2d/releases) in GitHub, with tag in the form `v#.#.#`, and write a little release note
 5. Run `rake` to build the gem, then push it to [rubygems.org](https://rubygems.org) with `gem push ruby2d-#.#.#.gem`
 6. 🎉