Several improvements before second concert

- Add end timestamp to concerts
- Add ability to view booklets for past concerts
- Filled concerts/nadal2020nens.json

Change-Id: Ic83b0b46661d1557468b0ffe678ac78e794ec179
diff --git a/concerts/nadal2020nens.json b/concerts/nadal2020nens.json
index 1e927da..7f11ce4 100644
--- a/concerts/nadal2020nens.json
+++ b/concerts/nadal2020nens.json
@@ -2,5 +2,371 @@
   "title": "Concert de Nadal 2020",
   "subtitle": "Nens i nenes",
   "begins": 1608571800,
-  "songs": []
+  "ends": 1608598800,
+  "songs": [
+    {
+      "title": "Que tinguis un bon Nadal",
+      "author": "Nadala popular anglesa",
+      "performers": [
+        {
+          "instrument": "Veus i percussió",
+          "names": ["Inés Coll", "Marcos Cruz", "Júlia Ferreira", "Lucía Mayorgas", "Diego Merino", "Anna Ros", "Gabriel Dale Villalba", "Hugo Montero", "Virgínia Pesquer"]
+        },
+        {
+          "instrument": "Guitarres",
+          "names": ["Alejandro Mora", "Pablo Jiménez"]
+        },
+        {
+          "instrument": "Bateria",
+          "names": ["Xavi Martín"]
+        }
+      ]
+    },
+    {
+      "title": "Minuet en Sol major",
+      "author": "Johann Sebastian Bach",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Julia Ndanda"]
+        }
+      ]
+    },
+    {
+      "title": "Bailes",
+      "author": "Lamote de Grignon",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Natalia Cruz"]
+        }
+      ]
+    },
+    {
+      "title": "Campana del campanar",
+      "author": "Nadala popular",
+      "performers": [
+        {
+          "instrument": "Veus i percussió",
+          "names": ["Paula Alcaraz", "Nerea Martínez", "Unai Mendo", "Clara Girona", "Iván Vergara", "Guiu Xuclà"]
+        },
+        {
+          "instrument": "Piano",
+          "names": ["Carme Martínez"]
+        }
+      ]
+    },
+    {
+      "title": "Chandelier",
+      "author": "Sia",
+      "performers": [
+        {
+          "instrument": "Veu",
+          "names": ["Noa Chacón"]
+        },
+        {
+          "instrument": "Piano",
+          "names": ["Tesi Osuna"]
+        }
+      ]
+    },
+    {
+      "title": "Bohemian Rhapsody",
+      "author": "Queen",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Iker Serrano"]
+        }
+      ]
+    },
+    {
+      "title": "Oda a l'alegria",
+      "author": "Ludwig van Beethoven",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Marc Baena"]
+        }
+      ]
+    },
+    {
+      "title": "El pastoret",
+      "author": "Popular francesa",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Marc Baena", "Montse González"]
+        }
+      ]
+    },
+    {
+      "title": "Santa Nit",
+      "author": "Franz Grüber",
+      "performers": [
+        {
+          "instrument": "Guitarres",
+          "names": ["Carla Revilla", "Alan Gareth Villalba", "Paula Alcaraz", "Clara Girona", "Inés Coll", "Guiu Xuclà", "Nerea Martínez", "Iván Vergara"]
+        },
+        {
+          "instrument": "Piano",
+          "names": ["Marcela Bou"]
+        },
+        {
+          "instrument": "Violí",
+          "names": ["Anna Ros"]
+        },
+        {
+          "instrument": "Ukelele",
+          "names": ["Lucía Mayorgas"]
+        },
+        {
+          "instrument": "Bateria",
+          "names": ["Pol Sicart"]
+        }
+      ]
+    },
+    {
+      "title": "Jingle Bells",
+      "author": "Popular nordamericana",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Claudia Ponce", "Lucía Burgos"]
+        }
+      ]
+    },
+    {
+      "title": "Cançó de bressol",
+      "author": "Johannes Brahms",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Marcos Cruz", "Victor Martín"]
+        }
+      ]
+    },
+    {
+      "title": "Dies d'alegria",
+      "author": "Thord Gummesson",
+      "performers": [
+        {
+          "instrument": "Veus",
+          "names": ["Carlota Bou", "Natalia Cruz", "Montserrat González", "Júlia Sicart", "Laura Matencio", "Lucía Ariza", "Raquel Caballero", "Ester Sánchez"]
+        },
+        {
+          "instrument": "Guitarres",
+          "names": ["Alejandro Mora", "Pablo Jiménez"]
+        },
+        {
+          "instrument": "Bateria",
+          "names": ["Xavi Martín"]
+        }
+      ]
+    },
+    {
+      "title": "Març",
+      "author": "N. Baklanowa",
+      "performers": [
+        {
+          "instrument": "Violí",
+          "names": ["Júlia Sicart"]
+        },
+        {
+          "instrument": "Piano",
+          "names": ["Carme Martínez"]
+        }
+      ]
+    },
+    {
+      "title": "Serra que serra",
+      "author": "Nadala popular catalana",
+      "performers": [
+        {
+          "instrument": "Veus",
+          "names": ["Olaia García", "Oriol Macías", "Víctor Martín", "Erik Plata", "Iker Serrano", "Alan Gareth Villalba"]
+        },
+        {
+          "instrument": "Violí",
+          "names": ["Júlia Sicart"]
+        },
+        {
+          "instrument": "Piano",
+          "names": ["Carme Martínez"]
+        }
+      ]
+    },
+    {
+      "title": "Mi burrito sabanero",
+      "author": "Villancico colombiano",
+      "performers": [
+        {
+          "instrument": "Saxo",
+          "names": ["Marc Baena", "Marlon Gómez"]
+        }
+      ]
+    },
+    {
+      "title": "This House Is Not For Sale",
+      "author": "Bon Jovi",
+      "performers": [
+        {
+          "instrument": "Veu",
+          "names": ["Gabriel Dale Villalba"]
+        },
+        {
+          "instrument": "Guitarres",
+          "names": ["Alejandro Mora", "Pablo Jiménez"]
+        },
+        {
+          "instrument": "Baix",
+          "names": ["Gabriel Villalba"]
+        },
+        {
+          "instrument": "Bateria",
+          "names": ["Xavi Martín"]
+        }
+      ]
+    },
+    {
+      "title": "El noi de la mare",
+      "author": "Popular catalana",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Julia Ferreira", "Laura Matencio"]
+        }
+      ]
+    },
+    {
+      "title": "The pipers are coming",
+      "author": "Johann Sebastian Bach",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Noa Chacón"]
+        },
+        {
+          "instrument": "Bateria",
+          "names": ["Unai Mendo"]
+        }
+      ]
+    },
+    {
+      "title": "La patinadora",
+      "author": "J. Thompson",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Noa Chacón"]
+        },
+        {
+          "instrument": "Bateria",
+          "names": ["Unai Mendo"]
+        }
+      ]
+    },
+    {
+      "title": "Huahuanaca",
+      "author": "Nadala popular boliviana",
+      "performers": [
+        {
+          "instrument": "Veus",
+          "names": ["Marc Baena", "Lucía Burgos", "Kimberly Calizaya", "Júlia Ndanda", "Claudia Ponce", "Carla Revilla", "Ester Sánchez", "Lucía Ariza"]
+        },
+        {
+          "instrument": "Guitarres",
+          "names": ["Abner Llacha", "Víctor Martín", "Erik Plata"]
+        },
+        {
+          "instrument": "Bateria",
+          "names": ["Diego merino"]
+        },
+        {
+          "instrument": "Flautes travesseres",
+          "names": ["Raquel Caballero", "Marta Albiol"]
+        },
+        {
+          "instrument": "Percussió",
+          "names": ["Unai Mendo"]
+        }
+      ]
+    },
+    {
+      "title": "Déjame",
+      "author": "Los Secretos",
+      "performers": [
+        {
+          "instrument": "Guitarres",
+          "names": ["Abner Llacha", "Víctor Martín", "Erik Plata"]
+        },
+        {
+          "instrument": "Bateria",
+          "names": ["Pol Sicart"]
+        }
+      ]
+    },
+    {
+      "title": "Oda a l'alegria",
+      "author": "Ludwig van Beethoven",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Olaia García", "Kimberly Calizaya"]
+        }
+      ]
+    },
+    {
+      "title": "Mad World",
+      "author": "Roland Orzabal",
+      "performers": [
+        {
+          "instrument": "Piano",
+          "names": ["Carlota Bou", "Marcela Bou"]
+        }
+      ]
+    },
+    {
+      "title": "Minuet",
+      "author": "C. Stamitz",
+      "performers": [
+        {
+          "instrument": "Flauta travessera",
+          "names": ["Raquel Caballero", "Marta Albiol"]
+        }
+      ]
+    },
+    {
+      "title": "Récréation de la Flauta Màgica",
+      "author": "W. A. Mozart",
+      "performers": [
+        {
+          "instrument": "Flauta travessera",
+          "names": ["Raquel Caballero", "Marta Albiol"]
+        }
+      ]
+    },
+    {
+      "title": "All I Want for Christmas Is You",
+      "author": "Mariah Carey",
+      "performers": [
+        {
+          "instrument": "Veu",
+          "names": ["Lucía Ariza", "Raquel Caballero", "Noa Chacón", "Ester Sánchez"]
+        },
+        {
+          "instrument": "Piano",
+          "names": ["Adrià Vilanova"]
+        },
+        {
+          "instrument": "Guitarres",
+          "names": ["Alejandro Mora", "Pablo Jiménez"]
+        },
+        {
+          "instrument": "Bateria",
+          "names": ["Xavi Martín"]
+        }
+      ]
+    }
+  ]
 }