Revert "Remove file storage possibility for now (awaits #12)"

This reverts commit 801ac8adbb.

assets/templates/html/index.html.tmpl

@@ -8,10 +8,13 @@ the command line.
 
 ## USAGE
 
+    # Upload a file
+    curl -F'file=@yourfile.png' <a href="{{.Request.Host}}">{{.Request.Host}}</a>
+
     # Shorten a URL
     curl -F'shorten=http://example.com/some/long/url' <a href="//{{.Request.Host}}">https://{{.Request.Host}}</a>
 
     # Shorten a URL with a token to delete it later
     curl -F'shorten=http://example.com/some/long/url' -F'deleteToken=' <a href="//{{.Request.Host}}">https://{{.Request.Host}}</a>
 </pre>
-{{end}}
+{{end}}

assets/templates/txt/index.txt.tmpl

@@ -6,6 +6,9 @@ the command line.
 
 ## USAGE
 
+    # Upload a file
+    curl -F'file=@yourfile.png' {{.Request.Host}}
+
     # Shorten a URL
     curl -F'shorten=http://example.com/some/long/url' https://{{.Request.Host}}