Added a test for successful storage of markdown in documentation

To satisfy DSDEEPB-46. Acceptance Criteria:
```
* There exists a metadata field which can accept a large (10KB) markdown representing tool documentation.
* There exists a unit test that validates that a 10kb string of github markdown is recovered without getting garbled
```

The metadata field exists. Here I'm adding the test. I made a little md file containing various markdown features.
I am concatenating that until it would be >10kb stored, and sending that through the webservice.

I am doing this the full way through the service, not just as a db test, because I want to make sure
serialization/deserialization and spray marshalling etc. do not garble the string.

src/test/resources/TESTMARKDOWN.md

@@ -0,0 +1,52 @@
+Basic Text
+Here is some text that includes some "double quotes" and some 'single quotes' and some "combinations 'thereof'".
+It {(also) [includes]} <some\> /extra \special \ncharacters. Think \*they'll be ~ok\?
+!@#$%^&*,.?;:=/-+
+
+# Headings
+# The largest heading (an <h1> tag)
+## The second largest heading (an <h2> tag)
+### The third largest heading (an <h3> tag)
+#### The fourth largest heading (an <h4> tag)
+##### The fifth largest heading (an <h5> tag)
+###### The sixth largest heading (an <h6> tag)
+
+# Line Breaks
+Below is a line break
+=====
+
+# Block-Quotes
+> This is a blockquote. It "includes" some quotation marks.
+
+# Text Styling
+**This _is_ a string that combines both bolds and italics.**
+
+# Lists
+This is a nested list that combines both unordered and ordered list with multiple levels of indenture.
+1. Item 1
+  1. A corollary to the above item.
+  2. Yet another point to consider.
+2. Item 2
+  * A corollary that does not need to be ordered.
+    * This is indented four spaces, because it's two spaces further than the item above.
+    * You might want to consider making a new list.
+3. Item 3
+
+# Code Formatting
+Here is some text with `monospacing`, within which text appears `**AS**IS`.
+
+# Code Blocks
+```
+# Here is a block of code
+x = 0
+x = 2 + 2
+what is x
+```
+
+# Links
+Here is a regular link:
+Scala](http://www.scala-lang.org/)
+Here are some image links:
+[![Build Status](https://travis-ci.org/broadinstitute/agora.svg?branch=master)](https://travis-ci.org/broadinstitute/agora?branch=master)
+[![Coverage Status](https://coveralls.io/repos/broadinstitute/agora/badge.svg?branch=master)](https://coveralls.io/r/broadinstitute/agora?branch=master)
+

src/test/scala/org/broadinstitute/dsde/agora/server/AgoraTestData.scala

@@ -11,6 +11,15 @@ trait AgoraTestData {
 
   val documentation = "This is the documentation"
 
+  def getBigDocumentation: String = {
+    // Read contents of a test markdown file into a single string.
+    val markdown = io.Source.fromFile("src/test/resources/TESTMARKDOWN.md").getLines() mkString "\n"
+    markdown * 7  // NB: File is 1.6 Kb, so 7* that is >10kb, our minimal required storage amount.
+  }
+
+  // NB: save io by storing output.
+  val bigDocumentation: String = getBigDocumentation
+
   val owner = "bob the builder"
 
   val payload = """task wc {
@@ -50,4 +59,13 @@ trait AgoraTestData {
     owner = owner,
     payload = badPayload
   )
+
+  val testAddRequestBigDoc = new AgoraAddRequest(
+    namespace = namespace,
+    name = name,
+    synopsis = synopsis,
+    documentation = bigDocumentation,
+    owner = owner,
+    payload = payload
+  )
 }

src/test/scala/org/broadinstitute/dsde/agora/server/webservice/ApiServiceSpec.scala

@@ -50,4 +50,9 @@ class ApiServiceSpec extends FlatSpec with Matchers with Directives with Scalate
     }
   }
 
+  "Agora" should "store 10kb of github markdown as method documentation and return it without alteration" in {
+    Post(ApiUtil.Methods.withLeadingSlash, marshal(testAddRequest)) ~> methodsService.postRoute ~> check {
+      responseAs[AgoraEntity].documentation === bigDocumentation
+    }
+  }
 }