Added the Blowfish theme

.gitmodules

@@ -0,0 +1,4 @@
+[submodule "themes/blowfish"]
+	path = themes/blowfish
+	url = https://github.com/nunocoracao/blowfish.git
+	branch = main

README.md

@@ -1,3 +1,4 @@
 # Blog
 
-> My personal blog, powered by [Hugo](https://gohugo.io/)
+> My personal blog, powered by [Hugo](https://gohugo.io/) and the
+> [Blowfish](https://blowfish.page/) theme

config/_default/hugo.toml

@@ -1,3 +1,4 @@
 baseURL = "https://nicolabelluti.me/"
-languageCode = "en-us"
-title = "Nicola's Blog"
+
+# https://github.com/nunocoracao/blowfish
+theme = "blowfish"

config/_default/languages.en.toml

@@ -0,0 +1 @@
+title = "Nicola's Blog"