Added README.md to lighthouse plugin

plugins/lighthouse/README.md

+# Lighthouse plugin
+
+This plugin issue lighthouse tickets.
+
+To use it, add `lighthouse` to the plugins array in your zshrc file:
+
+```zsh
+plugins=(... lighthouse)
+```
+
+## Aliases
+
+| Alias | Command                                | Description                                          |
+|-------|----------------------------------------|------------------------------------------------------|
+| lho   | `open_lighthouse_ticket`               | Opening lighthouse ticket                            |
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