Fix plugin class (#56)

Author: phortx

package.json

@@ -47,7 +47,7 @@
     "@types/graphql": "^0.12.3",
     "@types/inflection": "^1.5.28",
     "@types/lodash-es": "^4.17.0",
-    "@vuex-orm/core": "^0.26.2",
+    "@vuex-orm/core": "^0.26.4",
     "apollo-cache-inmemory": "^1.1.7",
     "apollo-client": "^2.2.2",
     "apollo-link": "^1.2.0",

src/index.ts

@@ -1,12 +1,12 @@
 import VuexORMGraphQL from './vuex-orm-graphql';
-import { Components } from '@vuex-orm/core/lib/plugins/use';
+import { Components, Plugin } from '@vuex-orm/core/lib/plugins/use';
 import { Options } from './support/interfaces';
 
 /**
  * Plugin class. This just provides a static install method for Vuex-ORM and stores the instance of the model
  * within this.instance.
  */
-export default class VuexORMGraphQLPlugin {
+export default class VuexORMGraphQLPlugin implements Plugin {
   /**
    * Contains the instance of VuexORMGraphQL
    */

yarn.lock

@@ -193,9 +193,9 @@
     source-map "^0.5.6"
     vue-template-es2015-compiler "^1.6.0"
 
-"@vuex-orm/core@^0.26.2":
-  version "0.26.2"
-  resolved "https://registry.yarnpkg.com/@vuex-orm/core/-/core-0.26.2.tgz#f93c49499b4050117d8b05a20e9239fb94388c44"
+"@vuex-orm/core@^0.26.4":
+  version "0.26.4"
+  resolved "https://registry.yarnpkg.com/@vuex-orm/core/-/core-0.26.4.tgz#02b4454fc5a71f24c7f81ec9315329695a74bf2a"
 
 "@webassemblyjs/ast@1.4.3":
   version "1.4.3"