add user scripting with lua

config.toml

@@ -3,6 +3,7 @@ guarded_paths = ["/"]
 # A list of all allowed users. For GitHub it is a list of usernames.
 # For Google it is a list of emails
 allowed_users = ["lukasmwerner"]
+redirect_url = "http://localhost:3000/oauth/callback"
 
 [upstream]
 addr = "http://localhost:8080"
@@ -11,7 +12,11 @@ program = "rezepte"
 args = []
 
 [provider]
-kind = "github" # can `google` or `github`
+kind = "OAuth2" # can `google` or `github` or custom via an undefined name
+auth_url = "https://github.com/login/oauth/authorize"
+token_url = "https://github.com/login/oauth/access_token"
+scopes = ["read:user"]
 client_id = "<CHANGE_ME>"
 client_secret = "<CHANGE_ME>"
-redirect_url = "http://localhost:3000/oauth/callback"
+# lua script that contains the function: `get_user_info(token)` and returns a string
+info_script = "get_user_info.lua"