[web] Updated README.md.

web/README.md

-## Getting started
+## Requirements
 
 - Download [Hugo](https://gohugo.io/#action) and put it in your `PATH`
-- Install Node packages with `npm install` (or via `yarn`), *OPTIONAL* for SCSS and Javascript
-- Install Python packages with `pip install -r requirements.txt`, *OPTIONAL* for getting content from [Contentful](https://app.contentful.com/spaces/4nuqzxntzxks)
+- Install [Node.js](https://nodejs.org/en/), check if `npm` is in your `PATH`
+- Install [Yarn](https://yarnpkg.com/en/docs/install), *OPTIONAL* faster alternative to `npm install`
+- Install Python and `pip`, *OPTIONAL* for getting content from [Contentful](https://contentful.com)
+- Install [ParaView](http://www.paraview.org/download/), *OPTIONAL* for converting VTK output files to vtk.js-format for interactive web visualization, check if `pvpython` is either in the `PATH` or ParaView is installed in `/Applications/` on macOS or `/usr/local/opt/paraview` on Linux
+
+## Getting started
+
+- Inside the source-directory `ogs/web`:
+  - Install Node packages with `npm install` (or via `yarn`)
+  - Install Python packages with `pip install -r requirements.txt`, *OPTIONAL* for getting content from [Contentful](https://contentful.com)
+  - Run `npm run build` to build the site which is created in `public/`
+
+Alternatively you can simply run `make web` inside your build directory to install everything and build the site (this requires that `python`, `pip` and `npm` or `yarn` was found by CMake).
 
-Alternatively you can simply run `make web` inside your build directory to install everything and build the site (this requires that `python`, `pip` and `npm` was found by CMake).
+## Develop site with live-preview
 
-## Start servers and watchers
+In `ogs/web` run
 
     hugo server
 
+In your browser go to http://localhost:1313. As you make modifications to the site it will be rebuild and the page in the browser gets reloaded.
+
 If you want to modify css or javascript run `gulp` in another terminal:
 
     npm run gulp
 
-## Build site
+## Importing CMS content (Optional)
+
+In `ogs/web/import` rename `secret_example.py` to `secret.py` and fill in `accessToken`.
+
+In `ogs/web/import` run
+
+    python import.py
 
-    (cd import; python import.py) # Optional for fetching content from Contentful, needs credentials setup, rename `secret_example.py` to `secret.py`
-    npm run build
+This fetches articles from the CMS to e.g. `ogs/web/data/news.json`.
 
 ## Used components
 
@@ -34,7 +52,7 @@ If you want to modify css or javascript run `gulp` in another terminal:
 
 Use shortcode `img`:
 
-```
+```go
 {{< img src="../square_1e2_neumann_gradients.png" >}}
 ```
 
@@ -46,19 +64,26 @@ Optional parameters:
 - `class` - CSS class
 - `alt` - Alt text
 
-## Dump
+### Visualizations
+
+Use shortcode `vis`:
 
-### Serve converted meshes with S3
+```go
+{{< vis path="Elliptic/square_1x1_GroundWaterFlow/square_1e2_pcs_0_ts_1_t_1.000000.vtu" [height="300"] >}}
+```
 
-- Set CORS: http://stackoverflow.com/a/19557452/80480
-- Upload to e.g. http://s3-eu-central-1.amazonaws.com/jenkins-dump
-- Eventually add `crossdomain.xml` to the root of the bucket:
+`path` is relative to `ogs/web/static/vis/` and points to a converted data set, see below.
+
+Optional parameters:
 
-```xml
-<?xml version="1.0"?>
-<!DOCTYPE cross-domain-policy SYSTEM
-"http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
-<cross-domain-policy>
-  <allow-access-from domain="*" secure="false" />
-</cross-domain-policy>
+- `height` - In px
+
+----
+
+You can convert VTK output files to vtk.js format with:
+
+```bash
+npm run convert -- -e -i vtk-file.vtu -o output/path
 ```
+
+Run `npm run convert` to get a list of possible arguments.