Adds 'Dein' vim plugin manager support (#148)

* Adds 'Dein' vim plugin manager support

* Add missing comma

README.md

@@ -90,6 +90,7 @@ Just run `topgrade`. It will run the following steps:
   * [NeoBundle](https://github.com/Shougo/neobundle.vim)
   * [Vundle](https://github.com/VundleVim/Vundle.vim)
   * [Plug](https://github.com/junegunn/vim-plug)
+  * [Dein](https://github.com/Shougo/dein.vim)
 * Node
   * Run `yarn global update` if yarn is installed.
   * Run `npm update -g` if NPM is installed and `npm root -g` is a path inside your home directory.

src/steps/vim.rs

@@ -11,6 +11,7 @@ pub enum PluginFramework {
     Plug,
     Vundle,
     NeoBundle,
+    Dein,
 }
 
 impl PluginFramework {
@@ -23,6 +24,8 @@ impl PluginFramework {
             Some(PluginFramework::Vundle)
         } else if content.contains("plug#begin") {
             Some(PluginFramework::Plug)
+        } else if content.contains("dein#begin") {
+            Some(PluginFramework::Dein)
         } else {
             None
         }
@@ -33,6 +36,7 @@ impl PluginFramework {
             PluginFramework::NeoBundle => "NeoBundleUpdate",
             PluginFramework::Vundle => "PluginUpdate",
             PluginFramework::Plug => "PlugUpgrade | PlugUpdate",
+            PluginFramework::Dein => "call dein#install() | call dein#update()",
         }
     }
 }