Refactor remove role from user

frontend/api/model.js

@@ -134,4 +134,20 @@ export default class OpenAppStackModel {
         return ok;
       });
   }
+  removeRoleFromUser(username, role){
+    const vars = { username: username, role: role };
+    const removeRoleFromUser = `
+        mutation removeRoleFromUser($username: String!, $role: String!){
+          removeRoleFromUser(
+            username: $username,
+            role: $role
+          ){
+            ok
+          }
+        }`;
+    return this.graphQlClient.query(removeRoleFromUser, vars)
+      .then( ok => {
+        return ok;
+      });
+  }
 }

frontend/pages/users.vue

@@ -90,15 +90,11 @@ export default {
         });
       this.roles.forEach( role => {
         if(role.users.includes(username) && !user.roles.includes(role.name)){
-          var rmRoleMutation = 'mutation{removeRoleFromUser( role: "' + role.name + '", username: "' + username +'"){ok}}'
-          axios.post(
-            '/api/admin/graphql', {
-                query: rmRoleMutation
-                }).then((res) => {
-                    role.users.splice(role.users.findIndex( element => { return element == username }),1);
-            });
+          backend.removeRoleFromUser(user.username, role)
+            .then( ok => {
+              role.users.splice(role.users.findIndex( element => { return element == username }),1);
+          });
         }
-
       })
     },
     selectRole: function(roleName){