use push instead of replace in ensureURL

Author: crossjs

src/history/hash.js

@@ -59,7 +59,7 @@ export class HashHistory extends History {
 
   ensureURL () {
     if (getHash() !== this.current.fullPath) {
-      replaceHash(this.current.fullPath)
+      pushHash(this.current.fullPath)
     }
   }
 }

src/history/html5.js

@@ -61,7 +61,7 @@ export class HTML5History extends History {
 
   ensureURL () {
     if (getLocation(this.base) !== this.current.fullPath) {
-      replaceState(cleanPath(this.base + this.current.fullPath))
+      pushState(cleanPath(this.base + this.current.fullPath))
     }
   }