chore: add local build instructions

CONTRIBUTING.md

@@ -40,7 +40,7 @@ Fish and PowerShell, the latter of which is the default.
 2. Summon the Command Panel (Ctrl+Shift+P) and select `Codespaces: Rebuild Container`
    to rebuild your devcontainer. (This should take just a few seconds.)
 
-### Recompiling oh-my-posh within
+### Recompiling oh-my-posh
 
 The devcontainer definition preinstalls the latest stable oh-my-posh release at build time.
 
@@ -54,6 +54,23 @@ If the compile succeeds, `oh-my-posh --version` should reply:
 Should you somehow mess up your devcontainer's OMP install catastrophically, remember that
 if you do `Codespaces: Rebuild Container` again, you'll be back to the latest stable release.
 
+## Local development
+
+Make sure your local go version matches with the pinned version in [go.mod]. You can build
+oh-my-posh by navigating the to the `/src` folder and executing the following command.
+
+```bash
+go build -v -o /path/to/oh-my-posh(.exe)
+```
+
+### Running tests
+
+To execute the tests, run the following command from the `/src` folder.
+
+```bash
+go test "./..."
+```
+
 [themes-discussion]: [https://github.com/JanDeDobbeleer/oh-my-posh/discussions/categories/themes]
 [discord-link]: [https://discord.com/channels/1023597603331526656/1055533233309233252]
 [docs]: <https://ohmyposh.dev/docs>
@@ -64,3 +81,4 @@ if you do `Codespaces: Rebuild Container` again, you'll be back to the latest st
 [codespaces-link]: <https://github.com/codespaces/new?hide_repo_select=true&ref=main&repo=175405157>
 [devcontainer-ext]: <https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-containers>
 [timezones]: <https://en.wikipedia.org/wiki/List_of_tz_database_time_zones>
+[go.mod]: src\go.mod