Fix validation

schema.patch

diff --git a/lib/routes/admin-api/feature-schema.js b/lib/routes/admin-api/feature-schema.js
index 262ccdc..8039aac 100644
--- a/lib/routes/admin-api/feature-schema.js
+++ b/lib/routes/admin-api/feature-schema.js
@@ -40,7 +40,11 @@ const featureShema = joi
     .keys({
         name: nameType,
         enabled: joi.boolean().default(false),
-        description: joi.string(),
+        description: joi
+            .string()
+            .allow('')
+            .allow(null)
+            .optional(),
         strategies: joi
             .array()
             .required()
@@ -48,10 +52,10 @@ const featureShema = joi
             .items(strategiesSchema),
         variants: joi
             .array()
+            .allow(null)
             .unique((a, b) => a.name === b.name)
             .optional()
-            .items(variantsSchema)
-            .allow(null),
+            .items(variantsSchema),
     })
     .options({ allowUnknown: false, stripUnknown: true });
 
diff --git a/lib/routes/admin-api/strategy-schema.js b/lib/routes/admin-api/strategy-schema.js
index 3a61c01..7175e7b 100644
--- a/lib/routes/admin-api/strategy-schema.js
+++ b/lib/routes/admin-api/strategy-schema.js
@@ -6,7 +6,11 @@ const { nameType } = require('./util');
 const strategySchema = joi.object().keys({
     name: nameType,
     editable: joi.boolean().default(true),
-    description: joi.string(),
+    description: joi
+        .string()
+        .allow(null)
+        .allow('')
+        .optional(),
     parameters: joi
         .array()
         .required()
@@ -14,7 +18,11 @@ const strategySchema = joi.object().keys({
             joi.object().keys({
                 name: joi.string().required(),
                 type: joi.string().required(),
-                description: joi.string().allow(''),
+                description: joi
+                    .string()
+                    .allow(null)
+                    .allow('')
+                    .optional(),
                 required: joi.boolean(),
             })
         ),