chore: update README

Author: nigel.zheng

README.md

@@ -1,2 +1,73 @@
 # spring-security-oauth2-test
-spring-security-oauth2-test
+[![](https://jitpack.io/v/ahunigel/spring-security-oauth2-test.svg)](https://jitpack.io/#ahunigel/spring-security-oauth2-test)
+
+This library is helpful for integration test based on spring security, especially oauth2 for resource server, works 
+with `MockMvc`.
+
+It enhanced spring-security-test by mock an OAuth2 client or on behalf of user.
+
+Attach Map-based claims to mocked user as authentication details, the claims can be extracted from bearer jwt token.
+
+_Note: Most code came from the open network. I refactor and enhanced the code, then we have this java-library._
+
+## Features
+- @WithMockOAuth2Client
+- @WithMockOAuth2User
+    - mock an oauth2 user, attach claims to OAuth2Authentication details
+- @AttachClaims
+    - attach Map-based claims to current authentication, should work with @WithMockUser
+- @WithMockUserAndClaims
+    - enhanced @WithMockUser, attach Map-based claims as authentication details
+    - equal to @WithMockUser + @AttachClaims
+
+## How to use
+
+### Step 1. Add the JitPack repository to your build file
+```groovy
+allprojects {
+    repositories {
+        ...
+        maven { url 'https://jitpack.io' }
+    }
+}
+```
+## Step 2. Add the dependency
+```groovy
+dependencies {
+    implementation 'com.github.ahunigel:spring-security-oauth2-test:master-SNAPSHOT'
+}
+```
+## Step 3. Write test
+```java
+@WithMockOAuth2User(
+      client = @WithMockOAuth2Client(
+          clientId = "custom-client",
+          scope = {"custom-scope", "other-scope"},
+          authorities = {"custom-authority", "ROLE_CUSTOM_CLIENT"}),
+      user = @WithMockUser(
+          username = "custom-username",
+          authorities = {"custom-user-authority"}),
+      claims = {
+          @Claim(name = "user_id", value = "6", type = Long.class),
+          @Claim(name = "role_id", value = "1"),
+          @Claim(name = "is_social_user", value = "false")
+      })
+```
+or
+```java
+@AttachClaims(value = {
+  @Claim(name = "user_id", value = "6", type = Long.class),
+  @Claim(name = "role_id", value = "1"),
+  @Claim(name = "is_social_user", value = "false")
+}, claims = {ROLE_NAME, "ADMIN"})
+```
+Refer to https://jitpack.io/#ahunigel/spring-security-oauth2-test for details.
+
+## TODOs
+
+1. Mock full oauth2 process, add `bearer` token to request header to extract a `PreAuthenticatedAuthenticationToken`
+
+2. For oauth2 request, add ability to set ResourceServerSecurityConfigurer.stateless to false, maybe an 
+annotation like `@ResourceStateLess(false)`
+
+3. Add support for `RestTemplate`