Update README.md

Updated README.md to have a basic sample.

Author: cdmdotnet

README.md

@@ -1,3 +1,24 @@
 # ClickUpAPI
 
-C# / .NET / .NET Core Implementation for management ClickUp API.
+C# / .NET / .NET Core Implementation for management ClickUp API.
+
+## Sample Usage
+
+For OAuth2 Flow - see https://jsapi.apiary.io/apis/clickup20/introduction/authentication.html and https://jsapi.apiary.io/apis/clickup20/reference/0/authorization/get-access-token.html
+
+```
+var apitokens = new ParamsAccessToken(clientId, clientId, code);
+var api = ClickUpApi.Create(apitokens);
+var getTeamsResponse = api.GetAuthorizedTeams();
+if (getTeamsResponse.RequestStatus != HttpStatusCode.OK || !getTeamsResponse.ResponseSuccess.Teams.Any())
+  throw new AuthorisationException("Could not find any teams you are part of.");
+```
+
+For Personal Token - see https://jsapi.apiary.io/apis/clickup20/introduction/authentication.html
+
+```
+var api = new ClickUpApi(personalToken);
+var getTeamsResponse = api.GetAuthorizedTeams();
+if (getTeamsResponse.RequestStatus != HttpStatusCode.OK || !getTeamsResponse.ResponseSuccess.Teams.Any())
+  throw new AuthorisationException("Could not find any teams you are part of.");
+```