Update README.md with proper dev setup instructions

This commit adds the proper instructions to build EventStore.UI and also details the steps for fixing common errors when building the project.

Author: 321zer0

README.md

@@ -1,43 +1,100 @@
 # EventStore.UI
 
-The new user interface for Event Store. This is included as a submodule in the main [Event Store](https://github.com/EventStore/EventStore) repository.
+The user interface for Event Store. This is included as a submodule in the main [Event Store](https://github.com/EventStore/EventStore) repository.
 
-## Running new UI
+## Running the UI
 
-Currently there are two ways to run the new UI:
+Currently there are two ways to run the UI:
 
 * Open `index.html` located int `src` folder in browser.
 * Execute `gulp connect` - this command [gulp-connect](https://github.com/avevlad/gulp-connect) run webserver with LiveReload (see dev section for info how to set up gulp if you are new to it) - `gulp connect` needs `gulp` to run, please see Dev information on how to install it.
 
 ## Dev
 
-To start developing it's best to install few things
+To start developing, make sure you have the following requirements:
 
-#### 1. install [node.js](http://nodejs.org/) if you havent done that already
-#### 2. install [gulp.js](http://gulpjs.com/)
+#### 1. Install [node.js v10.20.1](https://nodejs.org/en/blog/release/v10.20.1/) **and** (Python 2.7)[https://www.python.org/download/releases/2.7/] if you haven't done that already.
+
+If you already have another version of node.js installed, `nvm` can be used to set node v10.20.1 as the active one:
+
+```
+nvm use 10.20.1
+```
+
+nvm for Windows can be downloaded [here](https://github.com/coreybutler/nvm-windows/releases)
+nvm for Linux can be downloaded here [here](https://github.com/nvm-sh/nvm/releases)
+
+After installing Python 2.7, make a copy of the executable `python.exe` found in `C:\Python27` with the name `python2.exe` so that there are 2 executables: `python.exe` and `python2.exe`. This is required otherwise the build script when running `npm install` in the steps below fails when it looks for these executables.
+
+If you don't want to make copies of the python executable, there's a workaround. The commands below will configure `npm` to use the same `python.exe` executable when it looks for `python` and `python2`:
+
+```
+npm config set python "C:\python27\python.exe"
+npm config set python2 "C:\python27\python.exe"
+```
+
+Furthermore, make sure the path `C:\Python27\` has been added to the `PATH` variable. In Windows, this can be tested as follows from the **PowerShell**:
+````
+Get-Command python
+Get-Command python2
+````
+
+On Linux, this can be checked as follows:
+````
+which python
+which python2
+````
+
+#### 2. Install [gulp.js](http://gulpjs.com/)
 
 ```
 npm install -g gulp
 ```
 
-#### 3. install all node packages in project
+#### 3. Install all node packages in the project
+
+```
+npm install
+```
+
+If you get MSBUILD, VS2017, or VC++ related errors, follow the steps below to install the missing dependencies:
+
+1. Download Visual Studio Professional 2017 (version 15.9) (Trial) setup from [here](https://my.visualstudio.com/Downloads).
+2. When you run the setup, go to the **Individual components** tab, then use the search box at the top to select these components:
+- Visual Studio C++ core features
+- VC++ 2017 version 15.4 v14.11 toolset
+- Windows 8.1 SDK
+- MSBUILD
+Note that other components might get added automatically; do not remove them.
+3. Click "Install", and then click on "Continue".
+4. Wait for setup to finish installing all the components and dependencies.
+5. Now run these commands in the EventStore.UI directory:
 
 ```
+npm clean-install
 npm install
 ```
 
-#### 4. install [bower](http://bower.io/)
+#### 4. Install [bower](http://bower.io/)
 
 ```
 npm install -g bower
 ```
 
-to install bower components
+to install bower components:
 ```
 bower install
 ```
 
-#### 5. gulp commands avaliable
+If you get the error message *"bower.ps1 cannot be loaded because running scripts is disabled on this system"*, run the command below in **PowerShell**:
+
+```
+Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
+```
+
+Then, run `bower install` again.
+
+#### 5. gulp commands available
 
 ```
 // starts webserver with live reload