Implement OAuth2 service provider functionality.

web/sass-files/sass/partials/_signup.scss

@@ -315,3 +315,18 @@
     }
 
 }
+
+.authorize-box {
+    margin: 100px auto;
+    width:500px;
+    height:280px;
+    border: 1px solid black;
+}
+
+.authorize-inner {
+    padding: 20px;
+}
+
+.authorize-btn {
+    margin-right: 6px;
+}