add login with custom token api

Author: anotherdev

firebase-auth-rest/core/src/main/java/com/anotherdev/firebase/auth/rest/api/IdentityToolkitApi.java

@@ -31,6 +31,9 @@ public interface IdentityToolkitApi {
     @POST("v1/accounts:signInWithIdp")
     Single<SignInResponse> signInWithCredential(@Body SignInWithIdpRequest request);
 
+    @POST("v1/accounts:signInWithCustomToken")
+    Single<SignInResponse> signInWithCustomToken(@Body SignInRequest request);
+
     @POST("v1/accounts:lookup")
     Single<JsonObject> getAccounts(@Body IdTokenRequest request);
 

firebase-auth-rest/core/src/main/java/com/anotherdev/firebase/auth/rest/api/model/SignInWithCustomTokenRequest.java

@@ -0,0 +1,20 @@
+package com.anotherdev.firebase.auth.rest.api.model;
+
+import com.google.gson.annotations.SerializedName;
+
+import org.immutables.gson.Gson;
+import org.immutables.value.Value;
+
+@Value.Immutable
+@Value.Style(strictBuilder = true)
+@Gson.TypeAdapters
+public interface SignInWithCustomTokenRequest extends SignInRequest {
+
+    @SerializedName("token")
+    String getCustomToken();
+
+
+    static ImmutableSignInWithCustomTokenRequest.Builder builder() {
+        return ImmutableSignInWithCustomTokenRequest.builder();
+    }
+}