docs about manual testing in development (#1882)

docs/CONTRIBUTING.md

@@ -14,14 +14,6 @@ $ export GOPATH=$HOME/go
 $ export PATH=$PATH:$GOPATH/bin
 ```
 
-## Dependency management
-
-TiDB Operator uses [retool](https://github.com/twitchtv/retool) to manage Go related tools.
-
-```sh
-$ go get -u github.com/twitchtv/retool
-```
-
 ## Workflow
 
 ### Step 1: Fork TiDB Operator on GitHub
@@ -112,6 +104,49 @@ $ make check
 This will show errors if your code change does not pass checks (e.g. fmt,
 lint). Please fix them before submitting the PR.
 
+#### Start tidb-operator locally and do manual tests
+
+We uses [kind](https://kind.sigs.k8s.io/docs/user/quick-start/#installation) to
+start a Kubernetes cluster locally and
+[kubectl](https://kubernetes.io/docs/reference/kubectl/overview/) must be
+installed to access Kubernetes cluster.
+
+You can refer to their official references to install them on your machine, or
+run the following command to install them into our local binary directory:
+`output/bin`.
+
+```
+$ hack/install-up-operator.sh -i
+$ export PATH=$(pwd)/output/bin:$PATH
+```
+
+Make sure they are installed correctly:
+
+```
+$ kind --version
+...
+$ kubectl version --client
+...
+```
+
+Create a Kubernetes cluster with `kind`:
+
+```
+$ kind create cluster
+```
+
+Build and run tidb-operator:
+
+```
+$ ./hack/local-up-operator.sh
+```
+
+Start a basic TiDB cluster:
+
+```
+$ kubectl apply -f examples/basic/tidb-cluster.yaml
+```
+
 #### Run unit tests
 
 Before running your code in a real Kubernetes cluster, make sure it passes all unit tests.

hack/local-up-operator.sh

@@ -33,6 +33,7 @@ This commands run tidb-operator in Kubernetes.
 Usage: hack/local-up-operator.sh [-hd]
 
     -h      show this message and exit
+    -i      install dependencies only
 
 Environments:
 
@@ -48,12 +49,16 @@ Environments:
 EOF
 }
 
-while getopts "h?" opt; do
+installOnly=false
+while getopts "h?i" opt; do
     case "$opt" in
     h|\?)
         usage
         exit 0
         ;;
+    i)
+      installOnly=true
+        ;;
     esac
 done
 
@@ -67,8 +72,13 @@ IMAGE_TAG=${IMAGE_TAG:-latest}
 SKIP_IMAGE_BUILD=${SKIP_IMAGE_BUILD:-}
 
 hack::ensure_kubectl
+hack::ensure_kind
 hack::ensure_helm
 
+if [[ "$installOnly" == "true" ]]; then
+    exit 0
+fi
+
 function hack::create_namespace() {
     local ns="$1"
     $KUBECTL_BIN create namespace $ns