implemented joining of times

frontend/src/routes/time/Index.svelte

@@ -59,6 +59,26 @@
         return result;
     }
 
+    async function joinTimes(evt, id1, id2){
+        evt.preventDefault();
+        evt.stopPropagation();
+        const url = api('time/join');
+        const res = await fetch(url,{
+            credentials : 'include',
+            method      : 'POST',
+            body        : `${id1}+${id2}`
+        });
+        if (res.ok){
+            error = null;
+            let json = await res.json();
+            delete times[id1];
+            delete times[id2];
+            times[json.id] = json;
+        } else {
+            error = await res.text();
+        }
+        return false;
+    }
 
     async function loadTimes(){
         const url  = api('time');
@@ -189,6 +209,9 @@
             {:else}
             <td class="start_end" onclick={e => toggleSelect(time.id)}>
                 {time.start}{#if time.end_time}<wbr>…<wbr>{time.start.startsWith(time.end_date)?time.end.substring(11):time.end}{/if}
+                {#if line>0 && Math.abs(sortedTimes[line-1].start_time - time.end_time)<100}
+                <button class="symbol join" title={t('join_objects',{objects:t('times')})} onclick={e => joinTimes(e, time.id, sortedTimes[line-1].id)} ></button>
+                {/if}
             </td>
             <td class="duration" onclick={e => {detail = time.id}}>
                 {#if time.duration}