feat: add docs about custom dashboard header

customization/plugins.mdx

@@ -165,8 +165,56 @@ return {
 📢 Please, check out [noice's official documentation](https://github.com/folke/noice.nvim)
 to see more plugin options.
 
+## Dashboard
 
+When you open Neovim using `nvim` command, you'll see a pretty simple dashboard:
 
+![Better Vim default dashboard](/images/customization/default-dashboard.png)
+
+You can customize the header of the dashboard by passing a table to `dashboard.header` 
+entry in `better-vim.lua` file:
+
+```lua better-vim.lua
+return {
+  dashboard = {
+    header = { "MY CUSTOM HEADER" },
+  },
+}
+```
+
+And you'll see something like this:
+
+![Better Vim custom dashboard](/images/customization/dashboard-custom-header1.png)
+
+You can use some ASCII Art to make this looks more like yourself:
+
+```lua better-vim.lua
+return {
+  dashboard = {
+    header = {
+      [[                                                                       ]],
+      [[                                                                     ]],
+      [[       ████ ██████           █████      ██                     ]],
+      [[      ███████████             █████                             ]],
+      [[      █████████ ███████████████████ ███   ███████████   ]],
+      [[     █████████  ███    █████████████ █████ ██████████████   ]],
+      [[    █████████ ██████████ █████████ █████ █████ ████ █████   ]],
+      [[  ███████████ ███    ███ █████████ █████ █████ ████ █████  ]],
+      [[ ██████  █████████████████████ ████ █████ █████ ████ ██████ ]],
+      [[                                                                       ]],
+    },
+  },
+}
+```
+
+And this is the result:
+
+![Better Vim custom dashboard with ASCII Art](/images/customization/dashboard-custom-header2.png)
+
+> [`MaximilianLloyd/ascii.nvim`](https://github.com/MaximilianLloyd/ascii.nvim/blob/master/lua/ascii/text/neovim.lua) plugin
+is the source of the above ASCII Art.
+
+Be creative!
 
 
 # Unload plugins