Merge pull request mattermost#1205 from mattermost/js-yarn-install

Added yarn install instructions

Author: JeffSchering

source/developer/dev-setup-archlinux.rst

@@ -49,9 +49,13 @@ Set up your development environment for building, running, and testing Mattermos
 
   ``pacman -S nodejs npm``
 
-6. Fork Mattermost on GitHub.com from https://github.com/mattermost/platform.
+6. Install Yarn.
 
-7. Download the Mattermost code from your forked repository:
+  ``pacman -S yarn``
+
+7. Fork Mattermost on GitHub.com from https://github.com/mattermost/platform.
+
+8. Download the Mattermost code from your forked repository:
 
   a. Create the directory for the code.
 

source/developer/dev-setup-osx.rst

@@ -19,11 +19,13 @@ Set up your development environment for building, running, and testing Mattermos
 
   ``brew install node``
 
-4. Install Go.
+4. Install Yarn. Go to https://yarnpkg.com/en/docs/install#mac-tab and follow the installation instructions.
+
+5. Install Go.
 
   ``brew install go``
 
-5. Set up your Go workspace:
+6. Set up your Go workspace:
 
   a. ``mkdir ~/go``
 
@@ -40,9 +42,9 @@ Set up your development environment for building, running, and testing Mattermos
 
     ``source ~/.bashprofile``
 
-6. Fork Mattermost on GitHub from https://github.com/mattermost/platform.
+7. Fork Mattermost on GitHub from https://github.com/mattermost/platform.
 
-7. Download the Mattermost code from your forked repository:
+8. Download the Mattermost code from your forked repository:
 
   a. Create the directory for the code.
 

source/developer/dev-setup-ubuntu-1604.rst

@@ -70,9 +70,11 @@ Set up your development environment for building, running, and testing Mattermos
 
       ``sudo apt-get install -y nodejs``
 
-6. Fork Mattermost on GitHub from https://github.com/mattermost/platform.
+6. Install Yarn. Go to https://yarnpkg.com/en/docs/install and follow the installation instructions.
 
-7. Download the Mattermost code from your forked repository:
+7. Fork Mattermost on GitHub from https://github.com/mattermost/platform.
+
+8. Download the Mattermost code from your forked repository:
 
   a. Create the directory for the code.
 

source/developer/dev-setup-windows.rst

@@ -13,7 +13,8 @@ Installing Developer Components on Windows
   d. Add the line ``{Docker-IP} dockerhost`` to ``C:\Windows\System32\drivers\etc\hosts`` using a text editor with administrator privileges.
 3. Download and install Node.js from https://nodejs.org/.
 4. Download and install Go 1.8 from https://golang.org/dl/.
-5. Fork Mattermost on GitHub.com from https://github.com/mattermost/platform, then:
+5. Install Yarn. Go to https://yarnpkg.com/en/docs/install#windows-tab and follow the installation instructions.
+6. Fork Mattermost on GitHub.com from https://github.com/mattermost/platform, then:
   a. ``cd ~/go``
   b. ``mkdir -p src/github.com/mattermost``
   c. ``cd src/github.com/mattermost``
@@ -22,8 +23,8 @@ Installing Developer Components on Windows
   f. ``git config core.eol lf``
   g. ``git config core.autocrlf input``
   h. ``git reset --hard HEAD``
-5. Install and setup babun from http://babun.github.io/.
-6. Setup the following environment variables (change the path accordingly):
+7. Install and setup babun from http://babun.github.io/.
+8. Setup the following environment variables (change the path accordingly):
 
   .. code-block:: batch