Merge branch 'docs-graphs-section-new-frontend-guide' into 'master'

Update the new frontend guide to specify the usage of d3

See merge request gitlab-org/gitlab-ce!18294

doc/development/new_fe_guide/development/components.md

 # Components
-> TODO: Add content
+## Graphs
+
+We have a lot of graphing libraries in our codebase to render graphs. In an effort to improve maintainability, new graphs should use [D3.js](https://d3js.org/). If a new graph is fairly simple, consider implementing it in SVGs or HTML5 canvas.
+
+We chose D3 as our library going forward because of the following features:
+
+* [Tree shaking webpack capabilities.](https://github.com/d3/d3/blob/master/CHANGES.md#changes-in-d3-40)
+* [Compatible with vue.js as well as vanilla javascript.](https://github.com/d3/d3/blob/master/CHANGES.md#changes-in-d3-40)
+
+D3 is very popular across many projects outside of GitLab:
+
+* [The New York Times](https://archive.nytimes.com/www.nytimes.com/interactive/2012/02/13/us/politics/2013-budget-proposal-graphic.html)
+* [plot.ly](https://plot.ly/)
+* [Droptask](https://www.droptask.com/)
+
+Within GitLab, D3 has been used for the following notable features
+
+* [Prometheus graphs](https://docs.gitlab.com/ee/user/project/integrations/prometheus.html)
+* Contribution calendars