docs: improve README, remove duplicate example

Author: teutat3s

Makefile

@@ -1,6 +1,6 @@
 default: install
 
-generate:
+docs:
 	go generate ./...
 
 install:

README.md

@@ -2,14 +2,27 @@
 
 Currently only supports maintaining DNS Zones and Records.
 
+- [Provider documentation](https://registry.terraform.io/providers/pub-solar/hostingde/latest/docs)
+
 ### Environment variables for provider configuration
 - Required: `HOSTINGDE_AUTH_TOKEN`, go to your [hosting.de profile](https://secure.hosting.de/profile) and create an API Key
 - Optional: `HOSTINGDE_ACCOUNT_ID`
 
 ### Quick start
+Copy the example `main.tf`, then run the following commands:
+
+```shell
+export HOSTINGDE_AUTH_TOKEN=your-token
+```
 ```shell
 terraform init
 ```
+```shell
+terraform plan -out "hostingde.plan"
+```
+```shell
+terraform apply "hostingde.plan"
+```
 
 ### Example `main.tf`
 ```
@@ -152,6 +165,12 @@ Compile and install the provider into your `$GOPATH/bin`
 make install
 ```
 
+Generate documentation to `docs/`
+
+```shell
+make docs
+```
+
 Run resource tests
 ```shell
 export HOSTINGDE_AUTH_TOKEN=YOUR-API-TOKEN