adding part 0 exercises

Exercise 0.5

@@ -0,0 +1,4 @@
+browser->server: HTTP GET https://studies.cs.helsinki.fi/exampleapp/spa.
+server-->browser: HTML-code
+
+end note

Exercise 01

@@ -0,0 +1,23 @@
+browser->server: HTTP GET https://studies.cs.helsinki.fi/exampleapp/notes
+server-->browser: HTML-code
+browser->server: HTTP GET https://studies.cs.helsinki.fi/exampleapp/main.css
+server-->browser: main.css
+browser->server: HTTP GET https://studies.cs.helsinki.fi/exampleapp/main.js
+server-->browser: main.js
+
+note over browser:
+browser starts executing js-code
+that requests JSON data from server 
+end note
+
+browser->server: HTTP GET https://studies.cs.helsinki.fi/exampleapp/data.json
+server-->browser: [{ content: "HTML is easy", date: "2019-05-23" }, ...]
+
+note over browser:
+browser executes the event handler
+that renders notes to display
+end note
+
+
+
+

Exercise-0.6

@@ -0,0 +1,11 @@
+browser->server: HTTP POST https://studies.cs.helsinki.fi/exampleapp/spa.
+server-->browser: HTTP status code 302
+browser->server: HTTP GET https://studies.cs.helsinki.fi/exampleapp/spa./main.css
+server-->browser: main.css
+browser->server: HTTP GET https://studies.cs.helsinki.fi/exampleapp/spa./main.js
+server-->browser: main.js
+browser->server: HTTP GET https://studies.cs.helsinki.fi/exampleapp/spa./json
+server-->browser: main.js
+browser->server: HTTP GET https://studies.cs.helsinki.fi/exampleapp/spa./data.json
+server-->browser: [{...},{...},{...}]
+end note