use circleci instead of travis (#511)

Upgrade rust-toolchain
Upgrade Tantivy
Warning: tantivy now use a different file format, search index may need to be deleted and recreated to work as intended
try to run compile twice in a row because sometime oomk is evil

plume-models/src/medias.rs

@@ -189,7 +189,7 @@ impl Media {
         let ext = remote_url
             .rsplit('.')
             .next()
-            .map(|ext| ext.to_owned())
+            .map(ToOwned::to_owned)
             .unwrap_or_else(|| String::from("png"));
         let path =
             Path::new("static")