Merge branch '15-fix-render-app' into 'master'

Resolve "Fix render app"

Closes #15

See merge request !14

android/gradle.properties

 org.gradle.jvmargs=-Xmx1536M
 android.useAndroidX=true
 android.enableJetifier=true
-app.versionName=1.2.5
-app.versionCode=11
+app.versionName=1.2.6
+app.versionCode=12

lib/screens/home.dart

@@ -99,9 +99,9 @@ class Home extends StatelessWidget {
             onPressed: () => pickLetter(myProvider),
             child: Text("🔀"),
           ),
-          myProvider.letter == '' ? null : Container(
-            margin: EdgeInsets.all(5),
-            padding: EdgeInsets.all(5),
+          myProvider.letter == '' ? Container() : Container(
+            margin: EdgeInsets.all(15),
+            padding: EdgeInsets.all(15),
             decoration: BoxDecoration(
               color: backgroundColor,
               borderRadius: BorderRadius.circular(4),
@@ -137,7 +137,7 @@ class Home extends StatelessWidget {
             onPressed: () => pickCategory(myProvider),
             child: Text("🔀"),
           ),
-          myProvider.category == '' ? null : Container(
+          myProvider.category == '' ? Container() : Container(
             margin: EdgeInsets.all(5),
             padding: EdgeInsets.all(5),
             decoration: BoxDecoration(