message: Add `Collaboration` section to contributing.md
diff: @@ -7,9 +7,18 @@ Before starting contributing we recommend reading the following guides:
  2. [react-reconciler docs](https://github.com/facebook/react/tree/master/packages/react-reconciler)
  3. [Yoga Layout docs](https://yogalayout.com/docs)
  -## Chat
  +## Collaboration
  -Feel free to check out the [#development](https://spectrum.chat/react-figma/development?tab=posts) channel on our Spectrum.
  +### Issues assigning
  +
  +For avoiding situations than two contributors started resolving the same issue, recommending:
  +
  +1. Make yourself assignee at issue, or, if you haven't rights for this, write a comment at the issue about you started making.
  +2. Move issue to "In Progress" column at [next](https://github.com/react-figma/react-figma/projects/2) board.
  +
  +### Development Chat
  +
  +Feel free to discuss any problem at the [#development](https://spectrum.chat/react-figma/development?tab=posts) channel on our Spectrum.
  ## Developing
  