message: Add readme tag to Cargo.toml for crates.io
diff: @@ -20,6 +20,7 @@ keywords = ["opengl", "gamedev"]
  categories = ["api-bindings", "rendering::graphics-api"]
  documentation = "https://docs.rs/glium"
  repository = "https://github.com/glium/glium"
  +readme = "README.md"
  license = "Apache-2.0"
  build = "build/main.rs"
  exclude = ["doc", ".travis.yml", "circle.yml"]
  