Add a Feature enum

Features are handed by Discord to guilds that meet requirements which
are most likely realistically arbitrary.

The 3 features at this moment are:

- INVITE_SPLASH
- VANITY_URL
- VIP_REGIONS

On decoding of the two guild structs, map these string values to enum
variants.

4 files changed, 28 insertions, 3 deletions

diff --git a/definitions/enums/feature.yml b/definitions/enums/feature.yml
new file mode 100644
index 0000000..a9f935c
--- /dev/null
+++ b/definitions/enums/feature.yml
@@ -0,0 +1,24 @@
+---
+name: Feature
+description: >
+  A special feature, such as for VIP guilds, that a [`Guild`] has had granted to
+  them.
+
+    [`Guild`]: struct.Guild.html
+variants:
+  - variant: InviteSplash
+    description: >
+      The guild can set a custom [`splash`][`Guild::splash`] image on invite
+      URLs.
+
+        [`Guild::splash`]: struct.Guild.html#structfield.splash
+    name: INVITE_SPLASH
+  - variant: VanityUrl
+    description: >
+      The guild can set a Vanity URL, which is a custom-named permanent invite
+      URL.
+    name: VANITY_URL
+  - variant: VipRegions
+    description: >
+      The guild has access to VIP voice channel regions.
+    name: VIP_REGIONS
diff --git a/definitions/structs/guild.yml b/definitions/structs/guild.yml
index 44567e3..40518e0 100644
--- a/definitions/structs/guild.yml
+++ b/definitions/structs/guild.yml
@@ -22,7 +22,8 @@ fields:
     type: hashmap
   - name: features
     array: true
-    type: string
+    custom: Feature::decode_str
+    type: Feature
   - name: icon
     optional: true
     type: string
diff --git a/definitions/structs/live_guild.yml b/definitions/structs/live_guild.yml
index ed2aafe..0b027ca 100644
--- a/definitions/structs/live_guild.yml
+++ b/definitions/structs/live_guild.yml
@@ -18,7 +18,7 @@ fields:
     type: hashmap
   - name: features
     array: true
-    type: string
+    type: Feature
   - name: icon
     optional: true
     type: string
diff --git a/src/model/guild.rs b/src/model/guild.rs
index e8aff56..460f5ca 100644
--- a/src/model/guild.rs
+++ b/src/model/guild.rs
@@ -309,7 +309,7 @@ impl LiveGuild {
             channels: public_channels,
             default_message_notifications: req!(try!(remove(&mut map, "default_message_notifications")).as_u64()),
             emojis: try!(remove(&mut map, "emojis").and_then(decode_emojis)),
-            features: try!(remove(&mut map, "features").and_then(|v| decode_array(v, into_string))),
+            features: try!(remove(&mut map, "features").and_then(|v| decode_array(v, Feature::decode_str))),
             icon: try!(opt(&mut map, "icon", into_string)),
             id: id,
             joined_at: try!(remove(&mut map, "joined_at").and_then(into_string)),