Refactor to avoid deserialization failure

Author: Mark-Simulacrum

src/github/client.rs

@@ -120,7 +120,7 @@ impl Client {
     }
 
     pub fn fetch_pull_request(&self, pr_info: &PullRequestUrls) -> DashResult<PullRequestFromJson> {
-        if let Some(url) = pr_info.get("url") {
+        if let Some(url) = &pr_info.url {
             Ok(self.get(url, None)?.json()?)
         } else {
             throw!(DashError::Misc(None))

src/github/models.rs

@@ -1,6 +1,5 @@
 // Copyright 2016 Adam Perry. Dual-licensed MIT and Apache 2.0 (see LICENSE files for details).
 
-use std::collections::BTreeMap;
 use std::i32;
 
 use chrono::{DateTime, Utc};
@@ -50,7 +49,10 @@ pub struct LabelFromJson {
     name: String,
 }
 
-pub type PullRequestUrls = BTreeMap<String, String>;
+#[derive(Debug, Deserialize)]
+pub struct PullRequestUrls {
+    pub url: Option<String>,
+}
 
 #[derive(Debug, Deserialize)]
 pub struct IssueFromJson {