Add Jasmine tests for `OAuthRememberMe`

spec/javascripts/fixtures/oauth_remember_me.html.haml

+#oauth-container
+  %input#remember_me{ type: "checkbox" }
+
+  %a.oauth-login.twitter{ href: "http://example.com/" }
+  %a.oauth-login.github{ href: "http://example.com/" }

spec/javascripts/oauth_remember_me_spec.js

+import OAuthRememberMe from '~/oauth_remember_me';
+
+describe('OAuthRememberMe', () => {
+  preloadFixtures('static/oauth_remember_me.html.raw');
+
+  beforeEach(() => {
+    loadFixtures('static/oauth_remember_me.html.raw');
+
+    new OAuthRememberMe({ container: $('#oauth-container') }).bindEvents();
+  });
+
+  it('adds the "remember_me" query parameter to all OAuth login buttons', () => {
+    $('#oauth-container #remember_me').click();
+
+    expect($('#oauth-container .oauth-login.twitter').attr('href')).toBe('http://example.com/?remember_me=1');
+    expect($('#oauth-container .oauth-login.github').attr('href')).toBe('http://example.com/?remember_me=1');
+  });
+
+  it('removes the "remember_me" query parameter from all OAuth login buttons', () => {
+    $('#oauth-container #remember_me').click();
+    $('#oauth-container #remember_me').click();
+
+    expect($('#oauth-container .oauth-login.twitter').attr('href')).toBe('http://example.com/');
+    expect($('#oauth-container .oauth-login.github').attr('href')).toBe('http://example.com/');
+  });
+});