Enhance the community website homepage

The enhancement includes addition of materialize
css, JQuery, responsiveness, and easy-navigation
of website features. The easy-navigatibility is
achieved by adding a navbar with display of meta
-review and gamification leaderboard on homepage.
Apart from this, the activity graph url is omitted
from website by displaying the graph itslef on the
homepage on large devices.

Closes coala#255

data/migrations/0006_auto_20190615_1331.py

@@ -0,0 +1,18 @@
+# Generated by Django 2.1.7 on 2019-06-15 13:31
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('data', '0005_contributor_location'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='contributor',
+            name='teams',
+            field=models.ManyToManyField(related_name='contributors', to='data.Team'),
+        ),
+    ]