Make slug length same as name length

Generally slug is generated from it so it should hold about same length.
Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/trans/migrations/0034_auto_20150618_1140.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('trans', '0033_auto_20150618_1138'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='project',
+            name='slug',
+            field=models.SlugField(help_text='Name used in URLs and file names.', unique=True, max_length=100, verbose_name='URL slug'),
+        ),
+        migrations.AlterField(
+            model_name='subproject',
+            name='slug',
+            field=models.SlugField(help_text='Name used in URLs and file names.', max_length=100, verbose_name='URL slug'),
+        ),
+    ]

weblate/trans/models/project.py

@@ -80,6 +80,7 @@ class Project(models.Model, PercentMixin, URLMixin, PathMixin):
     slug = models.SlugField(
         verbose_name=ugettext_lazy('URL slug'),
         db_index=True, unique=True,
+        max_length=100,
         help_text=ugettext_lazy('Name used in URLs and file names.')
     )
     web = models.URLField(

weblate/trans/models/subproject.py

@@ -92,6 +92,7 @@ class SubProject(models.Model, PercentMixin, URLMixin, PathMixin):
     slug = models.SlugField(
         verbose_name=ugettext_lazy('URL slug'),
         db_index=True,
+        max_length=100,
         help_text=ugettext_lazy('Name used in URLs and file names.')
     )
     project = models.ForeignKey(