Add setup guide for Linux and refactor the doc

docs/setup.md

@@ -1,7 +1,8 @@
 # Mattermost Desktop Setup Guides
 
-## Step-by-step Windows setup
+## Installation
 
+### Windows
 To set up the Mattermost desktop application for Windows 7, 8 and 10:
 
 1. Download [the latest release](https://github.com/mattermost/desktop/releases) of Mattermost Desktop
@@ -18,15 +19,62 @@ To set up the Mattermost desktop application for Windows 7, 8 and 10:
    - Right-click the file and select "Pin to Start Menu" to make the application available from your Windows Start menu.
    - Double-click the file to open the application.
 
-4. After opening the application, press `Alt` key to bring up the menu at the top of the window, then click `File -> Settings`
 
-5. For each Mattermost team you'd like to use, enter its **Name** and **URL** then click **Add**
+### OS X
+For OS X 10.11 El Capitan. An older version of OS X has similar way.
 
-6. Click **Save** to save your setting
+1. Download [the latest release](https://github.com/mattermost/desktop/releases) of Mattermost Desktop
 
-   You're now ready to use electron-mattermost to interact with multiple teams from one desktop application
+   Find the file ending in `-osx.tar.gz`.
+
+2. From the `/Downloads` directory double-click on the file."
+
+   A new directory should be created on your Mac.
+
+3. Go to `/mattermost-desktop...` directory and right-click on `Mattermost` package and select "Open"
+
+   If you see a dialog to confirm the application, select "Open".
+
+   You should see a new application called **Mattermost Desktop** open.
+
+
+### Linux
+For Ubuntu 16.04.
+
+1. Download [the latest release](https://github.com/mattermost/desktop/releases) of Mattermost Desktop
+
+   Find the file ending in `-linux-*.deb`.
+
+2. Open a terminal and execute a command
+
+   `sudo dpkg -i mattermost-desktop-<VERSION>-<ARCH>.deb`
+
+3. Open Dash (located at top left corner) and input `mattermost`, then click `Mattermost` icon
+
+   You should see a new application called **Mattermost Desktop** open.
+
+
+## Configuration
+You have to configure the application to interact with your teams.
+
+1. Open **Settings Page**. If you use the application for the first time, **Settings Page** should appear automatically.
+   You can also see **Settings Page** by following methods.
+
+   - Windows: Press `Alt` key to bring up the menu at the top of the window, then click `File -> Settings`.
+   - OS X: Click `Mattermost` from the menu at the top of the screen, then click `Preferences...`.
+   - Linux: Click `File -> Settings` on the menu.
+
+2. For each Mattermost team you'd like to use, enter its **Name** and **URL** then click **Add**
+
+3. Click **Save** to save your setting
+
+You're now ready to use electron-mattermost to interact with multiple teams from one desktop application.
+
+
+## Quit
+- Windows, Linux: `Ctrl+Q`
+- OS X: `Command+Q`
 
-   To quit, use `Ctrl+Q`
 
 ## Help
 
@@ -39,7 +87,8 @@ The Mattermost desktop application offers:
 
 See the Mattermost [help documention](http://docs.mattermost.com/help/getting-started/signing-in.html) for how to use the Mattermost team site.
 
-### Settings Page
+
+## Settings Page
 
 The Settings Page is available from the **File** menu under **Settings** (Click `Alt` to show the menu if it's not visible). This page manages connections to team sites and other settings.
 
@@ -49,17 +98,18 @@ The Settings Page is available from the **File** menu under **Settings** (Click
 - **Delete a Team Site**:
    - Delete a Team Site by clicking the "x" next to the URL of the team site you wish to delete.
 - **Options**
-   - **Hide Menu Bar**
+   - **Hide Menu Bar** (Windows, Linux)
       - This option hides the menu bar. Press "Alt" to show it.
    - **Allow insecure contents**
       - If your team is hosted on `https://`, images with `http://` are not rendered by default.
         This option allows such images to be rendered, but please be careful for security.
 
-### Menu Bar
+
+## Menu Bar
 
 Click the `Alt` key to toggle the menu on and off.
 
-Below lists menu options (shortcut keys are listed in brackets):
+Below lists menu options (shortcut keys are listed in brackets, `Ctrl` becomes `Command` on OS X):
 
 - **File**
   - **About Mattermost** - Shows version information for Mattermost desktop application
@@ -78,42 +128,16 @@ Below lists menu options (shortcut keys are listed in brackets):
   - **Toggle Full Screen** (F11) - Toggle application from window to full screen and back
   - **Toggle Developer Tools** (Ctrl+Shift+I) - Turn on and off sidebar showing developer tools
 
-### Notifications
+
+## Notifications
 
 Mattermost lets users configure [desktop notifications](http://docs.mattermost.com/help/getting-started/configuring-notifications.html#desktop-notifications) to alert users to new events in a team site.
 
 For the Mattermost Windows application, these appear as ballon notifications from the task bar on Windows 7 and Windows 8.1, and as a "toast" pop-up on Windows 10.
 
-### Start Menu and Task Bar shortcuts
 
-If pinned to the Windows Start Menu in Step 3 of the setup procedure, a shortcut to the Mattermost desktop application should be available from the Start Menu by pressing the Windows Key.
+## Start Menu and Task Bar shortcuts (Windows)
 
-If pinned to the Windows Task Bar in Step 3 of the setup procedure, a shortcut to the Mattermost desktop application should be available from the Windows Task Bar.
+If pinned to the Windows Start Menu in the setup procedure, a shortcut to the Mattermost desktop application should be available from the Start Menu by pressing the Windows Key.
 
-
+If pinned to the Windows Task Bar in the setup procedure, a shortcut to the Mattermost desktop application should be available from the Windows Task Bar.
-## Step-by-step OS X setup
-For OS X 10.11 El Capitan. An older version of OS X has similar way.
-
-1. Download [the latest release](https://github.com/mattermost/desktop/releases) of Mattermost Desktop
-
-   Find the file ending in `-osx.tar.gz`.
-
-2. From the `/Downloads` directory double-click on the file."
-
-   A new directory should be created on your Mac.
-
-3. Go to `/mattermost-desktop...` directory and right-click on `Mattermost` package and select "Open"
-
-   If you see a dialog to confirm the application, select "Open".
-
-   You should see a new application called **Mattermost Desktop** open.
-
-4. Click `Mattermost` from the menu at the top of the screen, then click `Preferences...`
-
-5. For each Mattermost team you'd like to use, enter its **Name** and **URL** then click **Add**
-
-6. Click **Save** to save your setting
-
-   You're now ready to use electron-mattermost to interact with multiple teams from one desktop application
-
-   To quit, use `Command+Q`