update theme "ocean" README

themes/ocean/README.md

@@ -3,6 +3,9 @@
 A fish theme with ocean in mind.
 
 
+![Preview](preview.png)
+
+
 Unicode-compatible fonts and terminals is required.
 I would recommend iTerm2 + Solarized Dark for Mac users.
 This theme is based loosely on [agnoster](https://gist.github.com/agnoster/3712874)
@@ -14,6 +17,9 @@ This theme is based loosely on [agnoster](https://gist.github.com/agnoster/37128
 * Full path of current working directory
 * Git branch and dirty state (if applicable)
 * Show User @ Hostname if user is not default\_user
-> to turn on this feature, set these two lines in your config.fish
-> 	set -g theme display_user yes
-> 	set -g default_user your_default_username
+    to turn on this feature, set these two lines in your config.fish
+    ```
+    set -g theme display_user yes
+
+    set -g default_user your_default_username
+    ```