Fix template linting errors

app/components/add-contributor/template.hbs

@@ -13,7 +13,7 @@
             type="text"
             placeholder="0xF18E631Ea191aE4ebE70046Fcb01a436554421BA4"
             value=account
-            class=(if isValidAccount 'valid' '')}}
+            class=(if isValidAccount "valid" "")}}
   </p>
   <p>
     <select required onchange={{action (mut kind) value="target.value"}}>
@@ -26,39 +26,39 @@
             type="text"
             placeholder="Name"
             value=name
-            class=(if isValidName 'valid' '')}}
+            class=(if isValidName "valid" "")}}
   </p>
   <p>
     {{input name="url"
             type="text"
             placeholder="URL"
             value=url
-            class=(if isValidURL 'valid' '')}}
+            class=(if isValidURL "valid" "")}}
   </p>
   <p>
     {{input name="github_uid"
             type="text"
             placeholder="GitHub UID (123)"
             value=github_uid
-            class=(if isValidGithubUID 'valid' '')}}
+            class=(if isValidGithubUID "valid" "")}}
   </p>
   <p>
     {{input name="github_username"
             type="text"
             placeholder="GitHub username"
             value=github_username
-            class=(if isValidGithubUsername 'valid' '')}}
+            class=(if isValidGithubUsername "valid" "")}}
   </p>
   <p>
     {{input name="wiki_username"
             type="text"
             placeholder="Wiki Username"
             value=wiki_username
-            class=(if isValidWikiUsername 'valid' '')}}
+            class=(if isValidWikiUsername "valid" "")}}
   </p>
   <p class="actions">
     {{input type="submit"
             disabled=(is-pending inProgress)
-            value=(if (is-pending inProgress) 'Processing' 'Save')}}
+            value=(if (is-pending inProgress) "Processing" "Save")}}
   </p>
 </form>