Limit length of dictionary field

We need to fit into index on MySQL, which is 767 bytes (=191 chars with
utf8mb4).

Fixes #938
Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/trans/migrations/0001_initial.py

@@ -77,8 +77,8 @@ class Migration(migrations.Migration):
             name='Dictionary',
             fields=[
                 ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
-                ('source', models.CharField(max_length=200, db_index=True)),
-                ('target', models.CharField(max_length=200)),
+                ('source', models.CharField(max_length=100, db_index=True)),
+                ('target', models.CharField(max_length=100)),
                 ('language', models.ForeignKey(to='lang.Language')),
             ],
             options={

weblate/trans/migrations/0048_auto_20151120_1306.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('trans', '0047_project_source_language'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='dictionary',
+            name='source',
+            field=models.CharField(max_length=190, db_index=True),
+        ),
+        migrations.AlterField(
+            model_name='dictionary',
+            name='target',
+            field=models.CharField(max_length=190),
+        ),
+    ]

weblate/trans/models/dictionary.py

@@ -51,7 +51,7 @@ class DictionaryManager(models.Manager):
             target = unit.get_target()
 
             # Ignore too long words
-            if len(source) > 200 or len(target) > 200:
+            if len(source) > 190 or len(target) > 190:
                 continue
 
             # Get object
@@ -161,8 +161,8 @@ class DictionaryManager(models.Manager):
 class Dictionary(models.Model):
     project = models.ForeignKey(Project)
     language = models.ForeignKey(Language)
-    source = models.CharField(max_length=200, db_index=True)
-    target = models.CharField(max_length=200)
+    source = models.CharField(max_length=190, db_index=True)
+    target = models.CharField(max_length=190)
 
     objects = DictionaryManager()